Benjamin benjamin marauder

Trigger, valve, stock.
I think the #2 uses two breech screws and the #1 uses four but I am not sure.

There are a few other things too - gen 2 added a depinger, and changed the valve springs as well, but the biggest change was the repositioned trigger to improve ergonomics. Unfortunately that slightly degraded the trigger feel from the Gen 1 set up, at least in many people’s opinion (Gen 2 is still a good trigger, but Gen 1 was better at the cost of a poorer wrist angle). Of course the stocks and air tubes are not interchangeable.

The Gen 1 breech secured with three screws, with the one in the rear hidden under the bolt. On that version the bolt had to be removed to remove the Breech, but it meant the bolt could be pulled without taking down the whole gun. Gen 2 uses four screws to hold down the breech and all are visible with none hidden (neither good or bad, just how it is). The entire breech and barrel has to be removed to pull the bolt if you want to On Gen 2. That’s generally not a huge deal, but it can impact the ease of using a cleaning rod from the breech if you want to do so.

Can confirm the gen 1 stuff, I am one of the few with an early gen 1 floating around still with my gm barrel 25.