I have a 5-screw, fixed site 38 S&W CTg with number on butt of gun: 392132 Can you tell me year of manufacture?

First, let's clear up a discrepancy between your title and what you wrote in your post. I suspect the title is correct and that the cartridge legend on the barrel actually says, 38 S&W Special CTG. Is this correct?
The serial number would indicate shipment sometime around 1920, perhaps early 1921. There should be no Made in U.S.A. on the right side of the frame. The stocks should be sans-medallion and the stock circle should be convex.
Heat treatment of cylinders started in September, 1919, so yours would have a heat treated cylinder.
This would be called a 38 Military & Police revolver and probably has a square butt. Barrel length would be 4", 5" or 6". The last patent date on the barrel should be December 29, 1914.
Regards,
Jack

__________________
Jack
SWCA #2475, SWHF #318

The foregoing is correct if there is no letter prefix ahead of the number. If there is a V prefix, it would be later (1943). It might be possible to have a C-prefix, but that would be a little late for a 5-screw frame.