I stand corrected, there are top bolts in the 1933 Cabriolet convertible top.
I'll post a picture (f I can figure that out) and there is a washer between the bow and the frame.
Shoulder bolt:
Hex head 5/8 x .160 thick
Shoulder 3/8 diameter x .450 long
Thread is 1/4 28 x .290 long
.900 Overall...