해당 스레드에서 답변주신 
kboard_first_contents_mall_is_downloadable 필터를 사용하려고 history.php에서 사용된 방식과 해당 필터를 참고하여 아래와 같이 퍼스트콘텐츠몰 스킨의  document.php에 임의로 다운로드가 가능할때만 버튼이 활성화되도록 해보았으나 적용이 되지 않습니다..

<form method="post" action="<?php echo $url->set('uid', $content->uid)->set('mod', 'order')->toString()?>">
						<input type="hidden" name="<?php echo $order->getItemFieldName($content->uid, 'uid')?>" value="<?php echo $content->uid?>">
						<input type="hidden" name="<?php echo $order->getItemFieldName($content->uid, 'title')?>" value="<?php echo $content->title?>">
						<input type="hidden" name="<?php echo $order->getItemFieldName($content->uid, 'price')?>" value="<?php echo floatval($content->option->price)?>">
						<?php if(kboard_first_contents_mall_is_use_point_order($board) && $content->option->reward_point):?>
						<input type="hidden" name="<?php echo $order->getItemFieldName($content->uid, 'reward_point')?>" value="<?php echo floatval($content->option->reward_point)?>">
						<?php endif?>
						<input type="hidden" name="<?php echo $order->getItemFieldName($content->uid, 'quantity')?>" value="1">
						
						<h1><?php echo $content->title?></h1>
						
						<div class="image-gallery-wrap mobile-gallery">
							<?php if($media_list):?>
							<div class="kboard-first-contents-mall-image-gallery">
								<?php foreach($media_list as $media_item):?>
								<div data-thumb="<?php echo kboard_resize($media_item->file_path, 200, 200)?>" data-src="<?php echo site_url($media_item->file_path)?>">
									<img src="<?php echo kboard_resize($media_item->file_path, 600, 338)?>" alt="<?php echo esc_attr(basename($media_item->file_name))?>">
								</div>
								<?php endforeach?>
							</div>
							<?php endif?>
						</div>
						
						<dl class="detail-group">
							<?php if($content->category1 || $content->category2):?>
							<dt><?php echo __('Category', 'kboard')?></dt>
							<dd>
								<?php echo implode(', ', $content->getCategoryValues('<span>%s</span>'))?>
							</dd>
							<?php endif?>
							
							<dt><?php echo __('Seller', 'kboard')?></dt>
							<dd><?php echo apply_filters('kboard_user_display', $content->member_display, $content->member_uid, $content->member_display, 'kboard', $boardBuilder)?></dd>
							
							<dt><?php echo __('Period of use', 'kboard')?></dt>
							<dd><?php echo kboard_first_contents_mall_period_display($content->option->download_expiry)?></dd>
							
							<dt><?php echo __('Last updated', 'kboard')?></dt>
							<dd><?php echo date('Y-m-d', strtotime($content->update))?></dd>
							
							<?php if($content->option->price):?>
								<?php if($content->option->list_price):?>
								<dt><?php echo __('List price', 'kboard')?></dt>
								<dd class="list-price"><?php echo $board->currency($content->option->list_price)?></dd>
								<?php endif?>
								
								<dt><?php echo __('Price', 'kboard')?></dt>
								<dd class="price">
									<em><span id="amount-display"><?php echo $board->currency($content->option->price)?></span></em>
								</dd>
								
								<?php if(kboard_first_contents_mall_is_use_point_order($board) && $content->option->reward_point):?>
								<dt><?php echo __('Reward point', 'kboard')?></dt>
								<dd class="reward-point"><?php echo $board->currency($content->option->reward_point)?></dd>
								<?php endif?>
							<?php else:?>
								<dt><?php echo __('Price', 'kboard')?></dt>
								<dd class="price">
									<em><span id="amount-display"><?php echo __('For free', 'kboard')?></span></em>
								</dd>
							<?php endif?>
						</dl>
						
						<hr>
						
						<div class="kboard-document-detail-button">
						<?php if(kboard_first_contents_mall_is_downloadable()):?>
							<?php if($content->isAttached()):?>
								<?php foreach($content->attach as $key=>$attach):?>
								<button type="button" class="kboard-first-contents-mall-button-action" onclick="window.location.href='<?php echo $url->getDownloadURLWithAttach($content->uid, $key)?>'" title="<?php echo sprintf(__('Download %s', 'kboard'), $attach[1])?>"><i class="fas fa-download"></i> <?php echo $attach[1]?></button>
								<?php endforeach?>
							<?php endif?>
						<?php elseif($board->isOrder()):?>
							<?php if(kboard_first_contents_mall_is_current_user_order($board)):?>
								<?php if(kboard_first_contents_mall_is_downloadable($item->order_item_id)):?>
								<button type="submit" class="kboard-first-contents-mall-button-order"><?php echo __('Buy It Now', 'kboard')?></button>
								<?php endif ?>
							<?php else:?>
								<a href="<?php echo wp_login_url($_SERVER['REQUEST_URI'])?>" class="kboard-first-contents-mall-button-order" onclick="return confirm('구매하기 위해서는 먼저 로그인해야 합니다. 로그인 페이지로 이동할까요?');"><?php echo __('Buy It Now', 'kboard')?></a>
							<?php endif?>
						<?php else:?>
							<?php echo __('Sold Out', 'kboard')?>
						<?php endif?>
						</div>
					</form>