So far.
Mr. Martin. Mr. Schrager and Mr. Kohara.
All 3 did use 1 1/2" long butt caps in Delrin. The 3/8x10 brass screw almost looks to clean for that time, or maybe someone added the clean bullet nose to the screw. The wrap also looks very clean.
Mr. Martin use 3/8x8 and 3/8x10. The taper on the Forearm in the picture looks funky but doesn't look very different than the last Martin I worked on.
The Martin design on Mr. Koharas page in Blue book 3, the joint screw is hidden but his cues are known for 3/8x12 and 5/16x18 joint screws.
Mr. Schrager did use the 3/8x10 stainless but that doesn't eliminate that maybe he did a Martin style in brass and it sticks out longer, like other Schrager cues.
Above the butt cap, it looks like metal rings between the phenolic. It has me thinking there could be a 4th Cue maker whose name hasn't come up yet.
I hate being stumped but one thing is certain. I WILL NOT spray a finish on this cue. Wrap change maybe, which was asked for but only if I'm positive it's not a Harvey Martin.