G'day maaate- haven't heard from you in a while, but I don't live here so no surprise
As far as I know, ther's only one type of cover for the Plunger models, and the part # in the book is 67-1701, and the part# as I'm led to believe is 1# off the casting #, so at least it sounds close ..
The trouble you have could be due to the hollow 'dowell pegs' in front and rear screw holes being out of shape and not going in the corresponding inner-case holes ?? (assuming they are there)...if not that, and the clutch is installed, then the clutch may be sitting further out that it should be..I know it's a bitch to have to pull apart and check, but but did you do progressive dry run assembly of the cover and all other bits before adding in the clutch??