Generally it is the prefix letter of the serial number for example N102770 would be an N frame. It can also be ascertained by the model number. 25,27,28,29,57,58, 520 629 are N frames. 14,15,16,17,18,19,48,53,66,67,68 and their pre model versions are K frames.
N frame 357 Magnum
An N frame .357 Magnum revolver.
If you mean Smith and Wesson, inside the frame near the crane if it has one. Model numbers did not come into use until @ 1957
K frame.
Impossible to answer without the serial number.
It is a K frame. The original .357 Magnum was an N frame (Model 27). The K frame is smaller and lighter.
Yes
100-500 USD
L frame, .357 magnum, full length lug, 6 shot
The model 65 is built on the K frame.
Yes, a model 66 is a K frame revolver.
The smith and Wesson model 10 has the K service frame.