Unfired Rebuild Compression?

"Bottom end" meaning the camshaft too? If the engine's got "a couple hours on it" then the cam break in (or destruction) has already been taken care of. If you trust the guy (as opposed to "sort of trust") this should be a slam dunk. If you don't trust the guy, eitehr give it back and get money back, or get everything he told you in writing and signed by him.