Hi Andy,
I have 3 M82's almost complete, here is a list of what I need to finish them if you know of where I may find them. I do have all of what you have listed unfortunately.
3 X rear scope ring base blocks ( steel not alloy)
3 X adaptors to adapt the rear peep sight to the rear scope base. This is the piece that is bolted to the peep assembly that alows it to be attached to the rear base block when the scope has been removed.
3 X front sight base blocks.
3 X gun box's
3 X scope covers, if they had any at all.
Regards
GT