HOPEFULLY, someone will respond with an offer of a used bearing cover, if not, Depot parts, in Chilton, WI, has 3 of the Z976H covers ON HAND. They won't sell direct to you, but 'most all Deere dealers are set up to order from them, IF the WANT to HELP you.
You can go to their site, linked below, choose "GO TO PARTS ONLINE, then log in as "I Am NOT a Dealer", and check that part number. Enter it as I've posted it. You can call the Parts Depot to find out their nearest outlet in your area, IF your dealer doesn't deal with them.
The guards are INTERCHANGEABLE between most ALL DEERE mowers. If they can't exactly match what you have, there's ALL SORTS of currently available guards that will fit, and function right alongside the other guards, even though they MAY LOOK a bit different. Farm supply stores have generic guards, too. Just make sure the ones you get are listed as fitting DEERE mowers.
For guards at DEERE, try # AZ2131H, probably replaced by # AE36136, @ about $10.00 each
Ditto for the hold-downs... all sorts of choices at DEERE, or generic parts.
DEERE hold-downs... # Z7798H, replaced by # E127429, @ about $3.00 each.
One hold-down, that the strap on the sicklehead passes through is different, part # Z996H, replaced by part # AE57172, @ about $8.00.
The bare pitman stick is still available from Deere, as part # Z9298H, @ about $16.00. My local dealer has 3 on-hand, so they must not be TOO tough to get!
If you need the clamp parts for the pitman stick, they SHOULD be all available from DEERE, yet, too.
Take this info to the parts guy, and tell him to get off his butt, there's other stuff out here 'sides $200,000 new machinery!
Email me, if you have trouble getting someone to order you the cover.