Four years ago, I bought a 24H (from 1942) on Ebay USA (I'm located in Europe). Based on the description and pictures it didn't seem too risky.
I payed $354 for the horn and $20 for shipping within the States to my favorite repair man. According to his description I had overlooked quite a few dents in the bell, tuning slide, neckpipe, and slide. There was no inner slide wear, but the slide needed some making up.
The repair cost me $100, and shipping to Europe another $92. I don't remember exactly, but import tax must have been around $50.
All in all this amounts to about $600. In comparison, your friend's offer is quite reasonable, especially since the horn has been looked over, and - most importantly - you have the possibility to test it.
The 2B may be applicable in a wider range of situations, but the 24H has a very charming, singing voice of its own. Listen to e.g.
https://www.youtube.com/watch?v=yXebklad990
I have both horns and would not want to give away either of them.