Securing an Alaskan in the truck bed is done two ways, as you asked about there is the through-the-floor bolting system and the other is to simply secure the lower section where it flares out over the bed walls to either an under-frame system or to the front corner of the tub and rear bumper (or the outside of the tub wall using turnbuckles. There are plain-old turnbuckles and the ones designed for campers utilize a dampning system in them.
Since you have an 8' AK, you can close the tailgate which also acts as a "last resort" if things work loose, but let's not go there!
Both of the methods above involve drilling holes in the camper and should have strengthening gusset plates preferable above and below the plywood you are drilling through. "Fender Washers" were often used when the wood was new, but 50 years later we tend to want to spread out the surface even more so some triangular plates are a good idea.
The ones drilled out over the side of the truck are easy, you can get to them fairly well in the interior. The ones through the floor have to be aligned so they go through the AK and then the bed of the tuuck without destroying anything and be where you can bolt them tight. You have to sort out where the AK will ride in the bed so that you can use the tail gate of the truck and still not have the AK rubbing against the back of the cab or against the tub rim. The phrase, "Measure Twice, Cut Once" works here as well.
Structurally I suppose the through-the-floor method puts less stress on the side walls of the camper but if you have it set in there so it does not slide around and put stress on the mountings that is less of an issue...using a bedliner or in your situation, raising up the camper so it fits over the bed walls would allow for more movement so choose your poison here but perhaps the through-the-floor method would be preferable.
