353is

I'm looking at doing an LS1 swap into a 1995 bmw. It's been done by a lot of people and is well documented. I'm going to look at a local engine and trans in a few days and am looking for some advice. The LS1/t56 is said to be from a 2004 GTO that had approx. 58k and is complete. Ideally I would like to get the VIN and run a carfax so make sure the mileage is correct and see any other history, unfortunately the guy does not have that info. He did give me the numbers on the block, 12561168, can I gain any information from this block number? Can I find the VIN from the block number and then do a carfax? Any obvious things to look for when inspecting an already pulled engine and trans? Thank you.