I'm glad I can help, actually I put together a page on our website a few months back titled "Confederate Battle Flags Captured by the Pennsylvania Reserves" - It can be found here:
In addition, there are several other "stories" of men from the P.R.V.C. capturing flags, but there is no historical record of it. For instance, one soldier in the 4th Pennsylvania Reserves during the fighting on the Peninsula Campaign, captured a rebel flag; he states he was on his way back to his own lines, when he realized his rifle wasn't loaded. Accordingly, he laid the flag down on the dead body of a horse, and proceeded to load. When he was done, he turned back to pick up the flag and it was gone...just like that. Whether or not this story is true, I have no idea, and have found no other evidence supporting the fact. One of our site editors may know the story a little better, his name is Justin Sander's, you can get in touch with him through the website's contact form.
Another interesting story is that of Pvt. Isaac Clay, 1st Pennsylvania Reserves. Has been listed as a deserter for many years, but we are, piece by piece, collecting information that can rebuke that claim. Clay, late in life, struggled to get in touch with old comrades in Chester County trying to find somebody to clear-up the government's (or Bates') accusation that he was a deserter. Not only did he try hard to clear his name, but he also brought up a story about himself capturing a confederate flag at New Market Cross Roads (same campaign as above.) He says there were "many" witnesses to this, many men from the 71st Pennsylvania Infantry "Zouaves" witnessed it. Ironically, as he was passing by this zouave outfit, many men in one particular company recognized him because they were recruited from the same Chester County town Clay was from. Unfortunately, the story was never verified because most of the veterans were dead or gone away when Isaac tried to clear his name, and prove he captured a rebel flag. (End of story is, the flag was taken from Clay by a mounted general officer...who rode away with it.)
If you discover any other colors captured on the Peninsula Campaign, let me know - this may help us figure out which flag Isaac captured, if any.