Its simple. The cab had a diamond shape button setup. Most likely a metal cp.
Then explain the diamond being so crooked, not the same for each player, and angled?

I know you're basing your answer on the Dynamo "double diamond" control panel , but I don't think that's the case:

3rd panel being the best example( none of the 4th holes lined up with the pattern either)
I believe the guy got a Swiss cheese panel like I had with my old Dynamo:

And he just made the most of it. 3 year old tax sticker, and another one for 2016 about to expire, I think the game just isnt making any money on route anymore and he's getting rid of it.