I believe that metric plywood is made with special wood and can be folded in half. That way it is only 30" wide and can easily lay flat in the bed.Flush down on the deck?
My 2011 cannot. I kind of gummed up my carrying capacity, plywood-sheet-wise, but getting a Retrax box cover, but I believe that even without the Retrax, I could not get a sheet of metric plywood (60" x 60") in the bed.
Sure would like it, because I plan to get a G2 2017, and I use metric ply for projects.
You should probably go ahead and put a down payment on the new Ridge since your most important criteria is apparently a non issue . . .