Unless the cab was perfect (because the real silkscreened cab is the only thing the original has better than the decaled MMr), you are **probably** at $5000.
The used price had dropped to $6500 when MMr was announced, but now that the game is real and in people's hands, even that is too much.
Once you clean the playfield, you know there will be wear at the Blue Knight, and at the 2 shields at the top. You know there will be wear at Merlin's hole, shooter lane and the one pop bumper. Some of the inserts will need to be leveled.
The bar on the drawbridge is probably worn, the moat is probably cracked, dragon wings glued, plastics starting to yellow.
Flippers will need a rebuild kit for sure.
One or both troll mechs will need welding.
At least one wire ramp will need plating or welding.
Plastic ramps will be yellow.
Don't kid yourself how long fixing up a game that complicated will take.
So you might easily have 100 hours of work + $1000 in parts to restore that game. Add $900 more if you need a new playfield.
A MMr will give you ALL new parts, Stereo sound, color DMD (new software coming to fully colorize it), 2x clearcoated playfield, LED lighting, unfaded translight, one year warranty, and of course that NIB experience and smell.