How do you find out which frame a 38 caliber Smith and Wesson Chief's Special is?
It is a J frame.
The 38 Smith and Wesson Special is the full name for the 38 Special cartridge or revolver caliber with that designation, and so it is the same thing. The 38 Smith and Wesson Special cartridge is not the same as the 38 Smith & Wesson cartridge or 38 Long Colt cartridge, and should not be able to fit into those revolvers, but in rare cases it may, so use caution. (See Related Links)
What you have posted is the caliber of a firearm- the .38 Smith & Wesson CARTRIDGE (different from a .38 Special) Many companies made revolvers in this caliber- not just the Smith & Wesson Company (they invented that cartridge, so they got the naming rights) If you can repost will ALL markings on the weapon, and a description, we MAY be able to provide some information. Sorry-