Hey Donut,
I few years ago went to change the seals and found alot of rust/rot i half assed it at the time w fiberglass. this past fall i decided to tackle the problem and had to cutout and weld in all alot of new metal as well as the bottom windsheild corners. I know of a few other guys who have had the same issues.
I hope that yours is not as bad, but be prepared. If all is well under there, you may just need some adjusting, anti rattle strips or even a few body mounts.
I dont mean to scare you, i hope it is solid.
Mike