Soulless!Sam in Sam's head is wearing the same thing that Samifer wore in the Swan Song. Same jacket (the two-snap green), and same plaid shirt. It looks like that's what Hell!Sam is wearing too...so basically Sam's mind constructed the two Sam's from what they looked like when they were divided? Or his last known image of himself whole and with memories....so neat.
I do not know what this means, but it is awesome.
ETA: Also, I think I should take the time at some point to do a list of clothing per episode. Sometimes I have questions like "Is that the shirt that Sam wore in X-episode?" and my current categories don't really cut it for one-click answers.