Yes and no, I bought both the Plano 36" and the 42" rustrictor cases with the same intention and although it is possible there's a few issues I ran into. The easiest way to fit two AR's is to face them in opposite directions, lower receivers side by side with barrels pointing in opposite directions so overall barrel length can be an issue and shooting range staff might not be happy about firearms facing opposite directions as all firearms should be pointed down range even when cased so that was the first issue I tried to figure out. The next issue is your optics/risers and rifle height come into play as to whether or not they will fit the way I described above but there is a third option where you completely separate your upper and lower receivers. Pretty much what I ended up doing was put my rifles on a piece of carpet and tried to see the best way to fit them with a tape measure and no matter what I did mine were close to 16 inches wide laying down, side by side completely assembled so I went another route altogether. There's only a few hard cases on the market that are wide enough for two rifles with optics, one is a magpul daka and the others are pelicans, v730 v800 and v1745. I think the v730 is the only one comparatively priced case that you might find cheaper on sale. Not sure why so many manufacturers don't have wider cases but those were the only cases that I've been able to find after extensive research so I bought two more individual cases and now have each have their own case.
The dimensions of the Plano Rustrictor AW2 42 Rifle Case are 43"x14"x5".