I have a model 34 I was thinking of selling, so serial numbers would help identify it. I guess there are I frames and J frames.

No need for serial number.

The J frames are Model 34-1 and it will be marked on the frame thusly under the cylinder crane.

It is a 34-1, and the serial number starts with M, so that is post 1969.
Cool 34 story link below.

https://ogca.com/Legendary%20Kit%20Gun.pdf

Bluing is really bright, so pics were hard to take.

TerryK: How much is that tiny pistol?
TIA
BTT
Hold into the wind
VarmintGuy

Nice looking Kit Gun. It looks lightly used.