Are you sure it was the retailer that added the GTIN sticker? Sometimes bundled variants are split up by the publisher themselves - for example, the bundled version of"Final Fantasy X" in Australia was originally sold in a bundle with the PS2, but I've seen a handful of bundle versions sold with a stickered UPC that matches the official Australian release. This suggests that the publisher repurposed excess stock rather than the retailer.
I think that as long as a bundle entry in the DB is clear enough about it's contents then there's no need to add any of it separately. Although that may be wishful thinking since it's often hard to get good pics of oversized bundles like this one -
http://www.rfgeneration.c...nfo.pl?ID=E-215-S-01650-A
First of all, assuming you can find adequate info for the original bundle is definitely wishful thinking. The aforementioned Final Fantasy X bundle for Australia- to date I have only found ONE reference to the bundle itself, and that is a cruddy low-res image I found on Gumtree (not exactly a reliable source).
The European versions of this same bundle aren't much better.
I have also found that double packs are often split up by retailers -- the Capcom Classics double packs released in Europe in 2009/2010 are great examples of this.