Yes, I think the wooden interior Scamps have completely different cabinetry attachment.
The ones with fiberglass cabinetry seem to be like my Boler
. That is, the fiberglass cabinets are molded with a lip or flange that rolls out into the trailer from the cabinet, but along the wall or the roof. Then the rivets go through that lip and to the outside. So, if one were to attach blocks or make separate fiberglass lips, then it would require new/different holes through the faces/sides of the cabinets to attach them to the blocks. Not that that can't be done but on the other hand if one were to tab the cabinets right to the shell then you would not need new holes, and could even fill in the current ones.
I'll see if I can scare up a photo to add here.
Okay, here we go: If you look at the back of the kitchen counter and at the front/top of the upper cabinet, you can see the lips I am talking about. The fasteners go straight through them to the outside of the camper, so there is really no way to use those holes with blocks or etc. You could 'glass a block or fiberglass angle inside the cabinet in the corner, but then you would need a new fastener/hole through the face of the cabinet on the main body of it, not on the existing lip.
The benches are fastened more like how you are thinking, with blocks inside and fasteners through the "body" of the bench, but of course they are covered up by the cushions.
Here's one more that maybe shows the fasteners a bit more clearly: