60-66 Suburban/panel truck bed mounts and hardware???

[Chuck78]

GMC Paul's told me that they were not aware of anyone who makes Suburban/Panel Truck bed mounts (body mount bushings to frame). Does anyone have any idea if this is true? Previous owner changed out my bed wood to oak plywood sheets, but put it back together missing over half of the bed mount bushings. Some of the ones there are missing the bolts/nuts! I get a lot of creaking and flex around turns because of this, and need to fix this problem soon so I can haul heavy stuff.

I might have to start scrounging for a used set if it comes down to it. What a shame that they put it back together that way, as it looks like I have to take the bed wood back out to bolt the mounts in!