RM 649
The bottom gun in the OP is a prewar 357 frame ("made in USA" on the side plate, prewar RM hammer, prewar rear sight) with what is most likely a post war barrel which has been cut flush as noted above and had a slight ramp and a front sight affixed to the barrel (I think it is a post war barrel because of the "normal" "&" rather than the more pronounced "lazy" "&"). Also, note the lower side plate screw is of the postwar variety that is shorter with the flat head and is found under the grip horn on post war revolvers.
Fun thread!