[LT67]

Some of the plain ole 336 20in barreled rifles had no description. I have a 1978 336 in 30-30 and that's all it says on the barrel.

 

[LT67]

So if I understand the 336 history. It is safe to say that there is a model 336 (without any qualifier). Is it safe to say that this base model may change from year to year?

Yeah pretty much..... the 336 carbine with a 20in barrel with the mag tube extending all of the way to the end was basically the same for a long time. They also had a pistol grip butt stock as well. There are a few minor differences in different production years, but basically the same rifle. Hope this helps for you.