numrich gun parts at e-gunparts.com!
A guy on eBay has a store called Rediscovered Shooting Treasures (RST). He sells reproductions of the Marlin Model 120 manual.
numrich's gun parts has a fair selection of new and used parts for that firearm... http://www.gun-parts.com/marlin/
Call Chevy dealer ask for the phone number for the 'Service Manual'. Mine ran me about $120. About five or six books, eight inches high when stacked.
I presume you are asking about a Marlin model 120 pump action shotgun. In good condition a standard 120 is worth about $200-$250. If you are asking about The Revelation model 120 that was manufactured for Western Auto Supply by Marlin, then you are looking at a generic model 60. Worth about $75-$125 dependent on condition.
1300
Not recommended.
Call Target. They manufacture it and should be able to send you assembly instructions.
60-120
1300
If in like new condition $120-$150.
Is it a 12 guage Marlin 120? if so yes we have one and have done so.