The NCM 1x12 repro combo cabinet includes a slider board that hasn't been drilled.
I had to assemble the empty chassis halves with faceplate and fit it into the cabinet to determine where the holes will be drilled.
It ended up being off-center by about 8mm to the left (when facing the back of the amp) in order to get the faceplate to be centered in the cutout at the top.
Photo shows the lower chassis half just before drilling (you can't see the pencil lines on the slider board).
The two holes in the rear cover that attach to the top chassis half need to be moved to the left too (not shown).
FYI, the chassis halves and faceplate are made and sold by the same Steve from the UK on ebay that made the paxolin tagstrip boards. When shipping, ask him to pack it extra carefully. The one I ordered got damaged in shipping (one corner of the soft aluminum chassis half bent inwards). I'll have to figure out how to flatten/re-bend the dent out.
Next photo is of the Classictone transformers and choke installed in the lower chassis half, along with rubber grommets.
I originally planned to install the transformers flush against the chassis, but due to the copper shield curving a bit too far away from the power transformer's windings, I would either have to widen the rectangular hole in the chassis or raise the transformer off of the chassis to get it to fit. I decided to raise it a tiny bit using the plastic bushings that came with the bell cover.
The copper shield on the output transformer fit perfectly flush, but I raised it too to match the power transformer.