Joel,
How used?
I'm new to shooting, so I really couldn't answer the question. Didn't seem to be any wear that I could see externally
Any significant mods to the gun? (Still in warranty)
If there were, they didn't tell me
Does the Sig warranty carry over to the second owner?
It becomes a 1-yr craftsmanship warranty
Have you shot it?
No, they don't have a range at Cabellas (where I found the weapon)
Does the 'shop' stand behind the gun? (Moot if still in warranty)
30 day return policy if it's defective, otherwise no
Do you know the original owner? And why did he sell/trade it to the 'shop'?
Couldn't talk to him
Can you talk to the owner?
No =P
Enough questions?
As long as a decent answer comes out eventually, I'll answer all the q's I need to
This is what I would look for.