It looks like pictures I have seen of a "Frank Wesson 1860 rifle" (at http://buffaloclassic.tripod.com/). The numbers "3236" are stamped inside the shaft of the stock where the barrel fits; the barrel is about 23.5 inches long and the stock is about 22 inches.
Gun books would be a place to start
Blue book of gun values.
Impossible to answer. Requires hands on appraisal
No.
See Flayderman's "Guide to Antique American Firearms". Value can go up to multiple thousands depending on specifics.
Smith & Wesson semi-automatic rifle
50-500 usd
22 long rifle
About 7.5 lbs.
Started in 1983
100-500 USD
81-85