Thanks for the quick reply.
I found these which may be the originals. Do these look right?
Looks like 5/16 x 1-1/8 washer-head and 1" OD washers
I also found these 5/16 x 1" self-tapping bolts that look similar, along with a few 1-1/8" flat washers:
Which looks right?
Thanks,
Mike