1968 340S Coupe 4spd

Ok, so help me out with the basics. the first thing i want to do is verify the numbers on the drivetrain. IIRC, the engine is stamped on the drivers side- I need help decoding that for a match. If there is a reference that has this sort of info please just point me there. Second, and more improtantly is how to verify the tranny is matching. The 8 3/4 rear should have a tab with the gear ratio, but any other markings verify it as correct?

For those who asked: the price is not good. He wants too much.