Here's the Gumtwo cover on my 74'550K. Chrome trim and strap hardware is NOT included, but a new strap is.
Chrome trim came off the bike with a little effort, and I reused it.
Strap hardware- I assumed it was NLA. Reuse what you have.
I had a sheet of .5mm rubber, and cut a pad for under the sewn in seat top
Use plenty of upholsterers cement, and let it cure well before taking clamps off. If you use a chrome trim ring, this will also help keep the cover in place if a tooth is broken/missing.