Interesting! I know in the early 80's during the arcade boom manufacturers sold a lot of machines to operators via a yearly convention. It sounds like this unit was created for a similar purpose. If that's the case then you have an even rarer version of an already semi-rare cabinet. I've done a good bit of research on this cabinet and I've yet to come across anything about demo machines so this is all very intriguing to me. I wonder how your friend knew the back story on this cabinet?
As for the price, you for sure got a good deal. I've seen a few go in the $300-$500 range but I've seen most go for $1000-$2000 and above. I think it comes down to two things: (1) Does the owner know that he has a rare cab and (2) Is there anyone that wants the game. Even though the cab is rare, it's not a particularly good game. I think only a GB fan would pay the big bucks for one. I'm one of the ones that paid big bucks. I wanted this cabinet for 12 years. I felt that it was the only thing left to really complete my collection. Besides my pack, it's easily my fave GB item.
As far as the buttons go...here's what I used:
Red:
http://groovygamegear.com/webstore/inde ... cts_id=356 Yellow:
http://groovygamegear.com/webstore/inde ... cts_id=361 Blue:
http://groovygamegear.com/webstore/inde ... cts_id=359 You'll notice that you can select the switch type and if you want to keep the feel of the current button you should use True-Leaf Pro. It's a $1.49 upgrade per button but it was important to me to keep the buttons as accurate to the original as possible.
For the joystick...I wasn't sure how to go about replacing the entire stick so I just replaced the switches. The sticks seemed to be in good shape but they weren't registering certain directions. I only need a few switches but I just went ahead and replaced them all so I wouldn't have to worry it again.
http://groovygamegear.com/webstore/inde ... cts_id=346 All in all it cost me $45 after shipping and I had six new buttons and twelve new joystick switches. She plays perfectly now.