Back in the day, there was a place around my that built flatbeds for trucks. They would haul off and sale the OE beds. IDK if that is what this is, maybe not, but I have seen it before. I do agree it looks strange though.
Looks like Ram truck beds.They are not dually beds for sure, so flat beds are unlikely. Maybe a company bought some fleet trucks and had utility beds installed. Who knows rite. You are rite that they do look new.