This is extremely important to understand, because the definition of "rebuilt" varies wildly.

Rebuilt - Cleaned, new bearings, rings, valve job(which consists of what?), and a real nice paint job!

or

Rebuilt - Cleaned, crank fluxed and ground, bored cylinders, indexed block, line bored, new cam, cam bearings, lifters, new valve guides, valves, springs, and keepers, hardened valve seats installed. Honed w/ torque plates, etc, etc, etc.

Which engine would you rather have for $2500?

Find out, post his answer and we'll have a better idea. I had $1,800 in just my short block and I've been good friends with the shop owner for 20 years.