Here’s is some info on how can you tell if your Judge Dredd machine is an early production run machine or later production run. This will help you verify if you can run version L-1, or need L1-AT/L1-D instead. The early versions are not backwards compatible, however you can run the latest official rom (L7) in either version of the machine since it only has the virtual lock logic in the code.
Early production games included some features that were later removed due to cost/maintenance concerns.
1. “Ball on Magnet” switch on the crane magnet
2. Scoop may have a sticker that says “Pick A Prize” on early production machines. May have been removed by operators, but was a factory sticker on early machines.
3. Early production machines have a man holding a sniper rifle, where later machines have a crosshair on this plastic.
4. This plastic is typically green on early production machines.
5. Optos on right ramp (and Opto Board under playfield)
6. Actual prototype machines should have a red PCB, but later early production models would still be green.
Photo Credits: Andrew Jabrani and Pinsider mrofnoc