Potential Glock Purchase

I have a chance to pick-up a G22, and G17, both Gen 3, from a local range, that is "thinning the herd," on rental guns. 'Both guns are in great shape, and may have been back to Glock for a rebuild, at some point, as SNs on factory-barrels are different different from that on the frames. $300 ea. out-the-door, and each comes w/2 mags. 'Sounds good to me. Thoughts? 'Anything that I should look for?

Thanks.