Question for the knowledge bank.

I recently inherited a Marlin 336 in 30-30. been in the back of a closet for who knows how long.
Serial number says it was made in 1974.
The barrel is pitted out and it looks like the rear sight dovetail has been filed out too big for a new sight to be installed. (verified when I tried to install a new one)
I have been searching the parts sites and all can seem to find for a replacement barrel is for a 336TS in 30-30.
The question is, what is the difference between the "336" and the "336TS" and are the barrels interchangeable?

Thanks in advance for any help

The TS is the Texan and should be an 18.5" barrel

You mean the outside of the barrel is pitted or there is pitting in the bore.

Have it bored out to 38-55.