Selling a Rebuilt but Untested Motor, ..advice/thoughts? Options

[Literati914]

Looking for advice.. my latest 914, a '72 who's 1.7L engine WITH full D-jet fuel injection system, had supposedly just been rebuilt. I was told the engine was rebuilt by a friend of the owner, who was supposedly well versed in rebuilding VW engines. However the owner knew very little specifically about what was done and I got no receipts. He left it up to his friend/mechanic to "do it right" so to speak. You can plainly see that it's been stripped down and cleaned (certainly looks rebuilt at least). He'd just finished up the rebuild and the engine was never even reinstalled in the car or started (unless the builder did it on a stand, I don't know). It's absolutely complete - FI, induction, tin, clutch (said to be new), vacuum hoses (obviously new), etc, etc. It's just waiting to be installed and run.

The thing is I have a 2056cc 2.0L that I'm planning on using instead. So I'm gonna sell the original/rebuilt 1.7L and I'm wondering to what lengths I should go to verify the rebuild. What would you guys do? Pull heads (after pulling induction, FI, vacuum, ignition, etc, etc) (a bit of work) and photograph cylinders, etc? ... or just leave as is and try to get it started on a stand - then measure leak down and compression? Thoughts and considerations before I put it in the classifieds?