I don't see why these QARS or Quick Attach Rail System wouldn't work, but I have not tried them myself.
because it attaches like an Mlok - the old ones have a circle that fits the TRX rail with a BAR that has screw holes centered to the rail holes. Completely different systems. See the pic of the long rail section in the link you sent.
As stated earlier -- it's intended to be an improved attachment system for the exact same rail that doesn't require you to remove the rail to install, and prob also lighter weight. Unless they changed the dimensions or locations of the round holes, then it should work. Troy still sells new rails with round holes and seem to indicate that these should work with all previous gen, so don't believe there's any reason it won't work.
The holes male (picatinny rail) and female (handguard/rail itself) mating provides the strength. The clamping mechanism is merely to keep the rail on and in the event there's a perpendicular pull force on the rail, which would be unlikely. Notice that it's always been just two screws no matter the rail size? The threading junction between the screw and the backer is the weak point in this system, regardless of length or type of backer. Even magpul Mlok rails are only 2 screws until 4+", 9+ slot rails.
*And I'd have to double-check but I'm pretty sure the bar backers are aluminum and if these new similar to mlok backers are steel (magpul's mlok T nuts are steel), then they'd actually be stronger than the former bar at it's weakest point...
Try amazon with their easy returns if you're concerned. But again, it should work best as I and others can tell.