When I google for any of those part numbers I found sellers that show a picture showing very similar gaskets.
Found one seller in jaoan that actually have something that look more like the chain tensioner in shape. Likely the other sellers has mixed up the part numbers.
honda305.com Forum
Vintage Honda Owners, Restorers, Riders and Admirers
Latest Registry Entry
1965 Honda CP77 — Ulsan Metro City, Rep. Korea
Restored with original parts — Owner: J. Doe

