same as I explained for doing it on an item, cept in a different template. There are 115 +- templates in showcase, I've tried to name them as close to what they are for as possible. In this case, you are dealing with a THREAD, so you should look for a showcase template that deals with THREADs (listed below).
The template 'nflj_showcase_thread_view_header' has similar block of code that you asked about in the ITEM template. Just modify the <p class="tagLine muted"> towards the bottom of the template to format it how you want. That template has its own CSS file as well so you can style it and the Thread Tabs template directly without effecting anything else.
btw, you will probably want to edit the nflj_showcase_item_tab_reviews template as well as that has the same <div class="showcaseItemInfo"> BLOCK with the same information as on the ITEM page.