Am looking at purchasing a "Pre-10" with a five digit Serial Number C358XX. The Standard Catalog says they started using C1 in 1948 and ran until C999999. It doesn't give the end date or any numbers in between. Am I right to estimate this is a '48 or '49 production revolver?

Yes. Pretty certainly later 1948 production, could have shipped sometime into 1949, but I’ve seen a C 44-thousand shipped January 1949 recently.

C339xx shipped in 12/48. That is the closest SN on my list.

I see another one in the C339xx range that shipped in November, 1948. I also see one at C463xx that shipped in January, 1949.

I am quite certain that serials up to at least C44000 were assembled in 1948, as Absalom noted.

Since they did not ship in serial order, it is entirely possible yours left the factory in 1948, but 1949 might be a better guess. Without a letter, it remains only a guess.

__________________
Jack
SWCA #2475, SWHF #318