Hello,
I hope you may be able to answer a few of my gun questions.
I recently purchased a Griswold-Gunnison Model 20 Pistol. It has the original C.S.A. markings on both sides of its brass sides and in very good condition. My questions for this gun I will ask you below:

1. Should I clean this gun? if so, to what extent?
2. Were all these models .36 caliber?
3. The only serial number that I can find is located beneath
the gun and etched into the brass. The number is: 4029
Does this provide any significance as to where or who it may have been assigned? I'm also unsure of the exact date of manufacture, somewhere between 1860-1862.
4. What might this gun be worth in the next 20 years?
I will greatly appreciate any help that you may provide to me in answering my questions. Thank you very much.

Sincerely,
David Ray Tuck