Yeah, you are gonna want to take it all apart. The weights might be free, but the rollers they ride against inside the spider could be rusty and/or stuck. Most of the clutch is aluminum, but there are some steel parts in there. Water is not friendly in that combination. To either the aluminum or the steel.
Guessing that you probably already know this, but gonna throw it out there anyway.....Since it was too expensive for the PO to fix the front Diff, and with the clutch cover in that condition, I would give the machine a good going over to find what else was done badly or just let go.
Mine: 2018 Sportsman 850SP - 26" Bear Claw HTRs on OEM steel wheels(I really don't like the Aluminum ones)
Polaris Hand warmers, Mirrors.
Hers: 2019 Sportsman 450. 26" Bear Claw HTRs on Moose 427X Wheels.
2007 Sportsman 500 EFI, Polaris Winch, 25" Bear Claws QSC Clutch Kit, Hand Warmers
2001 Magnum 325 MOSE 12" rear wheel conversion. 25" Sedona Coyote tires
2017 Polaris Ranger 1000XP - Roof and front glass
2018 Kawasaki KLR650
2001 Magnum 325 Warn winch and Moose 60" plow-Sent to Daughter and Son-In-Law since his blew up
SOLD 2004 Sportsman 600 Twin