They say the Coin-Mech model number on one of the pages, so you could check to make sure it is a basic switch, I think some of the newer mechs use more complicated circuitry. The also spec ipac keyboard encoders, so provided it is a switch then hookup is real simple.
They look like a reasonable deal for a real clean cabinet fully functional w/ a newish computer, at least the upgraded version.
I am curios about the legality of their business though, not that I think they are out to be thieves, but they are selling the machine pre-configured to run MAME and MameWah. While they may have gotten permission to sell a cabinet with MameWah, I am sure that the MAMEDevs didn't give permission for MAME. It's too bad really because it would be hard to sell to the masses if it didn't work upon delivery, but allowing MAME machines to be bought and sold makes it hard to stand by the stated purpose of MAME development.