[MattNH]

I'm simplifying, in the early 60's Marlin started the "Glenfield Products" line for chain stores to be the more budget line as opposed the the Marlin name reserved for dealers. The rifles are identical function wise just birch wood for stocks instead of walnut. Most even have the "JM" stamp on the barrel. I have a Marlin 80G stamped Glenfield Products which is from 1960 or 1961 because it doesn't have a serial number and in 1962 there are date codes for month/year of manufacture stamped on the barrel. My Marlin 80G became the Glenfield 25 in 1966 when the Marlin Glenfield Products, became the Glenfield line.

Are you sure yours isn't stamped Marlin 36G? How do you know the stock is Walnut? Does it have the Marlin bullseye in the toe?

The Marlin 36G Glenfield Products was produced 1964 and 1965, which coincides with your "Z" prefix on the serial number. In 1966 it became the Glenfield 30. They are the same as the Marlin 336 with exception of the furniture, front sight and the shorter magazine tube.

 

[MattNH]

My Marlin's markings are lined up like in your picture.
No G, it is just marked Model 36. That is what is confusing. When you do a look up or search it either gives you the 1936 pre and post war gun or 336 model or 36G model.
On another forum there was the same question asked and no one knew the answer but three people on that forum had a rifle just like mine.
My friend, who is very on up on firearms and wood said he can tell by the grain and look, color etc. that it is Walnut not birch like most Glenfields had. He thought it might be a first run of the Glenfield line that they used walnut wood before they economized more by going to birch but he was just guess on that.

Valid explanation on the no-G as a very early run, also for the walnut, they used what they had so it could very well be a walnut stock without the bullseye. Car guys can get a little weird with "correct" parts, just like gun guys. In reality, it was a manufacturing environment in the 1960's, they needed to get stuff out the door and used whatever parts they had. Either way, you've got a nice Marlin/Glenfield rifle from 1964. I have my 1976 vintage 336 and almost like the idea of the shorter mag tube like yours.

Now, how about some pictures? I have since added a period correct hammer extension since these pics were taken.