Just to add to the fastener discussion, both the '50, and '49 'bolt, and my '49 Poncho used large Philips head screws to mount the regulators. Perhaps all were replaced!!
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics