Highly unlikely that sn info is available. Highly unlikely that sn info is available.
What year was the Butler derringer made. Serial 22500
Vintage gun parts such as the needed magazine for a Model 46A Western Field 22LR can be found at major gun shows or through online specialty companies such as APEX and Numrich.
Gun catalogs
A .22 Derringer.
Your wards/westernfield .22LR should read model 14M 488A.These rifles were made for montgomery wards by Mossberg.There Model number is Mossberg Model 50.You should be able to find some parts for your rifle at numrich gun parts corp.They can be found on the web.
Try e-gunparts.com
Try http://www.gunpartscorp.com/
Will depend on the make of derringer. They are not all the same. Would suggest you find a gunsmith to do this one. It is cheaper than taking one to them AFTER you work on it.
No published sn data.
Blue Book of Gun Values, on line auctions.
You will have to contact RTM to find out.