Jimmy/Blazer - rear seat installation with no mounting holes

[Woodsloafer]

Hello everyone,

I just bought a '72 Jimmy that did not come with a factory seat. I have an original seat (two front and four rear mounting brackets) but there are no holes in the bed to install it. I searched through threads here extensively but could not figure out whether there is reinforcement under the bed or not where the seat mounts on those that came from the factory with the seat installed. Is it a matter of drilling holes and welding nuts to underside of bed or does it need other reinforcement. Also, in some pictures I have seen what appears to be small plates in the bed on two or four of the rear brackets - do they have/need mounting plates for the seat brackets?

Again, I searched so as not to ask something already answered but I could not figure it out for sure.

Thank you for any assistance/guidance!