RM2-6202-000CN is a spare stapler module for Stapler Stackers CE405A and F2G72A.
The stapler module itself inevitably wears out and will become failure prone over time, either jamming or misfiring. The LaserJet 4200/4350 service manual gave a life rating of 50,000 pages for this modules predecessor. The module itself more or less just swivels into place and is connected by a single plug and socket.
To remove and replace the stapler unit
1 Turn the printer off
2 Rotate the stapler unit toward the front of the printer until the unit clicks. Hold the stapler unit in this open position.
3 There is a plastic tab with a pivot nub on the top of the stapler unit.
4 Hold the tab down and pull the stapler unit up and out of the stapler/stacker.
5 Disconnect the cable that connects the stapler unit to the stapler/stacker. (Only the blue part detaches.)
6 Remove the new stapler unit from its packaging.
7 Connect the cable on the new stapler unit to the stapler/stacker.
8 Place the pivot pin on the bottom of the new stapler unit into the hole in the stapler/stacker (in the cavity created by removing the old staple unit).
9 Press down on the tab at the top of the stapler unit and push the unit into the stapler/stacker.
10 Rotate the stapler unit toward the rear of the printer until the unit clicks into place.
11 If the stapler cartridge is not installed in the stapler unit, install it now.
The M604 Service Repair manual has pictures.