This would be best left to a qualified gunsmith to perform.
No.
Model variation
It depends on the model.
Might have been replaced.
I have a marlin model 60 with a gold trigger..the price difference is not by much if any at all..they both cost the same. some gun shops will charge more, but most usually don't and charge the same. A model 60 with etching and wood work can sell for more than one with just a gold trigger.
It is very easy to adjust the trigger on a Model 700 Remington. Remove the rifle from the stock and there is 3 small screws you can adjust. One is for the lbs. of trigger pull, which be careful you don't make it so easy it's a hair trigger and could go off just by the jar from closing the bolt. The other is to adjust the length of trigger pull.
no,plain and simple
Marlin- Mdl 80 with an adjustable trigger
Best left to a qualified gunsmith.
At a good gunsmith's shop. Maybe Numrich's Gun Parts (search gunpartscorp) For the complete trigger guard assembly, including trigger, safety, springs, pins etc., you can get it from Numrich, Midway USA, Brownells or direct from Marlin. If it's just the trigger or other individual trigger guard parts you need, you'll have to get those from Numrich for a different model Marlin.
The Marlin Model 3000 was the chain-store version of the Model 336. They added a gold trigger, gold bead sight and have no checkering.
Do not attempt this. Have it done by a gunmsith.