Looks to be in remarkably good condition, except for the missing sidecovers - polish it and ride off into the sunset ? Not from your description though.
Tough little motors though, has it seized from use/abuse or from standing ?
Bit of a description here
http://en.wikipedia.org/wiki/Honda_CD175Many Ondas had a date stamped onto the tag on the headstock, yours doesn't have. ?
Its possible to discreetly weld plates onto mufflers as a repair, particularly if they don't show, they look too good to discard ??