On the frame under the yoke.If your Smith and Wesson was made after 1958.If it was made prior to this year,it will have a serial number only.
The gun is likely a Harrington & Richardson (H&R) model 925. The caliber is .38 Smith and Wesson (S&W) special, not to be confused with .38 special (SPL). You must shoot the .38 S&W ammo, not .38 spl.
No such model number used by S&W.
You will have to call S&W to find out.
@ 1961
model is stamped on gun frame inside cylinder housing
There is no S&W Model 150
40-500 usd
Impossible to answer without the serial number.
@ 1979
You will either have to provide the serial number or call S&W.
Model numbers did not come into use until @1957
Early 1977