I bought this yesterday and so far I've been unable to track down the info I'm looking for.

Gun specifics..

1954 336A (s/n L9**)
35 Rem
18" barrel

Did Marlin make an 18" barrel or has someone cut and re-crowned through the years?

I have an older Marlin 336 in 30-30 w/ an 18" barrel. Its got a straight stock though, I believe its called a "Texan" model.

I have both a 336-A and two 336SCs from that era. The 336-As were rifles with 24" barrels and the SCs had 20" barrels however, I am not a Marlin expert by any stretch of the imagination. Thanks...Bill.

336A had 24" factory barrels. Sounds like yours was cut down.