Depending on condition, $25-$100.
Your Hopkins & Allen XL model was made between 1902-1914.These were a five shot double action.there value is not much,between 55-160 dollars.
It should be marked on the barrel or frame.
Unable to identify model from just the serial number. Need a detailed description of all markings, type of action, finish, caliber.
Impossible to value without a detailed description of all features and overall condition.
Caliber can not be idenitifed by sn. Take it to a gunsmith if it isn't marked on the frame or barrel.
10-100 USD or more depending on specifics.
Blue Book of Gun Values
ip adress
Impossible to answer without a detailed description of all markings, features, finish and caliber.
.45 calliber
50-500 USD depending on specifics
Cornell publications might have what you are looking for.