Don't know, haven't taken them apart yet. I doubt it, the motor mounts have a single through bolt too.
Once the design is finalized, welding will happen! No need to have them unbolt, make them solid.

I'd go with coilover shock mounts as opposed to the current coil spring pockets, but this is his call. To me, they fit the early to mid 60's time frame, and that front suspension is solidly at least a decade later if not two decades later.