Hey guys, I'm going to an arcade auction tomorrow morning and just hoped that maybe some of you experts would be up at this time to answer my question before I go

There is a Dragons Lair game there in really nice shape, perfect monitor and almost mint marquee and CPO (all original). The only problem is, when you hit a button or move the joystick, the game shows some numbers in the corner and SKIPS. I'm thinking this the laser disc player problem, but any ideas?
I'm trying to figure if this would be worth buying or not. And this auction is so low-profile, it will probably go for around $400 canadian ($275 US?)!!
Thanks in advance for any help