Custardtart - In the end, were you looking to build a truck or a short bed hotrod? If you were going for a truck, IMO, it came a long way to be with you and I'd take it as fate and run with it.
I'm building a truck. Mines a '51 3100 and I love it, but at times when I'm looking at photos or daydreaming about showing up to help a friend move or something I kinda wish it was a 3600 with a side mount spare and a skinny tire NAPCO conversion.
So, you bought and paid to have a 3100 shipped to you and the guy sent a 3600? Like, I buy a Corvette and the guy sends me a Nova so how do I turn the Nova into the Corvette I really wanted? And some guys are saying, what the heck, the Nova's a pretty good car so just be happy with it? Have you spoken to the guy?
Apples to oranges. The 3600 is a much, much closer relation to a 3100 than a Nova is to a Corvette. I realize that the short bed is more desirable to some, but honestly, if you couldn't tell a 3600 from a 3100 by looking at it without the badging, even just by looking at pictures, does it really matter which one you got so long as you got one?