Its not that the cab no good, having a cab changed from one game to another is surprisingly quite common in the arcade industry.
It is cheaper for the arcade owner to order a conversion kit for an existing cab that losing interest than to order a completely new machine when the game comes out.
It is a big reason why the SNK Neo Geo MVS machines were so popular for a long time, the arcade owner can swap out games from the cab with out modifications, just swap 1 art card and cartridge.
Example there is many Donkey Kong cabs that got converted to a Nintendo VS cabs (Nintendo VS cab is a arcade version of the NES hardware, and all its games are arcade versions of NES games).
I still remember going to a Mortal Kombat 3 Cab, was a Street Fighter II cab with the Street Fighter 2 Panel and side art still on the cab. Just the Marquee, cardboard monitor bezel and game inside had change.
So if you want a 100% authentic Tekken Cab, this is not it. From what others say, its a Tekken board inside what could me a MK cab. But if you want a affordable cab with Tekken 3 inside that is fairly good condition, I would till go for it if I had the space for it at home.