Agreed - the evidence does tend to weight on the side of Craft.
I've been looking to try and find an image of the left hand side of the Punisher cap and haven't been able to find one. Having said that, there are a large number of different versions of the Punisher cap and while I haven't seen a white-on-black cap from the left, there are other versions of the cap (black-on-white and red-on-black) that have the Marvel logo on the right hand side of the cap and the Marvel logo is, you guessed it, red and rectangular. So there is still an outside chance that it could be just a Marvel cap.
Like you said, though, you can order these for online... so big whoop, right.
Oh, and bitshare did a piece on this as well, and they have an interesting photo from behind some of these guys.
Not Craft, National Guard, but as these guys are more likely to be interested in military organisations, means they are more likely to buy the paraphernalia. You can read the Bitshare article here