There was a discussion not long ago about whether or not the retaining ring on the Bronco was the same one used on full-size pickups of that vintage too.
I don't remember if anyone said yay or nay on it, but the pickup version is available new from suppliers like LMC, which probably means Dennis Carpenter and Scott Drake as well.
I don't think we've sold them yet, but I would be very interested in hearing whether or not the two are the same.
Paul