Welcome to the forum.
As others have stated, you have 2 different revolvers in your photos. One having the large extractor rod knob and one with the small extractor rod tip that is the same diameter as the rod itself. There was a third version that was smaller than the large knob but slightly larger than the one in your photo. Just slightly larger than the diameter of the rod.
IIRC, the large knob disappeared in the late 20's and the medium was around into at least the 40's according to my information. Not sure exactly when the third size came into being but I am sure someone will be along with that information.
The serial number is the one on the butt. 452318. The other numbers are factory assembly numbers and were placed to keep parts that were fitted to each other together after the gun was disassembled for the application of a final finish. In your case nickel.
Being a family gun, if you are keeping it, you may wish to spend the $75 for a history letter to see if it shipped to anyone or place with significance. Many times it will only say it went to Joe's Hardware in Podunk, ID but once in a while it comes back with very cool information. Either way, if staying in the family, a history letter merely adds to the story.
If your grandfather is still alive you should ask him for the history so it can be written down and kept with the gun. If you are selling the gun(s), disregard the above.