I'm not sure that this cue is a Martin, although many things look similar to his work. It would be difficult for me to say this is a Martin because I have never seen one with that joint, a metal band in the buttsleeve, nor the wood ring above the wrap - and I have seen many, many Martins. But who knows, it could be a rare find of an earlier cue. Harvey did have a metal background as well as woodwork, so???
A little of my 'Martin' background: I moved to Los Angeles area beginning late 1976 where I worked a short while w/Bert Schrager, became great friends /Bert & his wife. I also became friends w/Allen Gilbert and George Aronek (and others that knew Harvey Martin) working a few times w/Gilbert on my 3-cushion. I played out of Tiff Payne's N. Hollywood Billiards. Gilbert brought Harvey to one of our sessions in a private home. This was one of the best experiences of my life getting to spend the day w/Harvey. He even showed me how he put on tips, which gave the same warm feeling I got when I watched my grandfather work when I was young.
My point is I saw many Martin cues and have talked to him about cuemaking and a this type of cue was never mentioned. But this sure doesn't mean it's not, but I would guess no.
Both Bert & Gilbert are dead so I think the best person to ask at his time may be George Aronek who used to be USBA (US 3-cushion Assoc) president and I believe still plays out of the Burbank Elks. He would at least be able to suggest another person - maybe Ernie Gutierrez from Gina cue fame?
Hope this helps.
Dave
One last thought - if the cue unscrews above the joint and the weight can be adjusted in the forearm, that would be a good sign it may be a Martin.