Rear axle question : center pin stuck on the ring.

Glad you got it apart. I'm sorry I missed the tag from @halifaxhops. I'm not getting notifications lately. That pin might have not been modified. Although I've never seen an 8.25 like that from the factory, it's certainly possible. GM used cross pins like that in a lot of their cars light and medium duty trucks. Remove the cross pin bolt, turn the cross pin to line up the groove, get the c clip out and so on. I was never a fan of c-clips. People have had the button on the end of the axle break off and lose the axle...although I've never seen it happen, I'm sure it has.