Real Short Bed Frame or Not?

[NotNuRodz]

Hi guys (and maybe gals?), I'm trying to determine if I have an original short bed frame or not. on the bottom half of the frame is looks like the back half of the frame could have been cut off then slid forward and riveted in place? Also in the the second picture you can see a line that looks like it could be a ground down weld. The last reason I think the frame may be cut down is because an unknown portion of the back was hacked off with a torch at some point.

When new, the truck was a service vehicle for a public school district. I was told it was ordered as a cab and chassis and then had a flat bed put on it. Also at some point someone started to hot rod the truck and put in a questionable amount of lowering blocks, just giving me another reason to think the frame was hacked up.

Let me know what you think. I just want to know I am working with a safe frame before I start digging into the truck more.

Thanks!
-Evan