Depends...
My first MAME cab doesn't have the monitor or PC held down in such a way that it can be moved without disassembling it. My second MAME cab can be moved without taking anything out. HOWEVER, with the monitor installed, these guys are HEAVY!
Cabinets that were put on route like the DK cab you are talking about should be able to be moved in any position (upright or laid down). But, if they were modded by someone, things might not be fastened down as they should be. As a result, you could end up with wires making contact during the trip (not necessarily a problem) that don't let lose when you stand it back up (potentially a problem).
Best bet is to check if everything is held tight in place before tipping it. If you don't check, you'll find out quickly! Good luck!
