Welcome to the forum Wilks,
The rack pictured is (was) the stock option for the later MGBs like my 78 Rubber Bumper. While I never tried - I assume that it would fit your older B. Either way as I understand all the truck (boot) lids are interchangeable.
Regardless if you really want on of these - I'd go ahead & grab the first one you can find, as these are no longer made and are getting kind'a hard to find. Folks are always asking me if I'd like to sell mine. Nope, not gonna happen! /ubbthreads/images/graemlins/nonono.gif
If the holes don’t match up perfectly - plug the old holes and mount the new one.
Good Luck!
/ubbthreads/images/graemlins/cheers.gif