Is it a 12 guage Marlin 120? if so yes we have one and have done so.
Yes
Answer the glenfield by marlin is compatible with marlin 120 12ga barrels are available for the 120 the only difference is the stocks wich are also interchangable the 120 is higher quality I love my glenfieldThat model is obsolete and you are not going to find a slug barrel. If you must use slugs, you can have the existing barrel modified to accept interchangeable choke tubes and use a rifled tube when shooting slugs.
You will have to measure the inside diameter of the barrel to find out if it is not marked.
I see no reason that you cannot.The steel shot sould work fine in your ranger model 120 shotgun.
Your model 120 ranger is worth 200.00 dollars in the condition you describe.
The model 120 ranger shotgun ranges in price from 90-170 dollars depending on the overall condition of the gun and a good bore.
I would look to Numrich gun parts corp.They may be found on the web.
90-180 dollars,depending on overall condition and a good bore.
Impossible to answer without a detailed description of all markings, finish, condition, box, papers, accessories, etc..
Between 170-200 dollars in the description that you have provided,including the original box and choke tube wrench.
80-120 depending on condition. I just bought one for 60
80-120 depending on condition. I just bought one for 60