Any Ram truck with GN/5th wheel prep package came/comes with FIVE holes in MY 2013 thru 2016 thus far.
I owned a 2013 with the GN/5th wheel prep package and that truck was identical to the 16 I now own....5 holes in the bed.., center hole for a GN and 4 outside holes for the picture frame adapter to put a hitch on, or, in my case now, to mount my B&W RVK3600 Companion hitch..
If truck only has 1 center hole, it was after market..ALL trucks manufactured with GN/5er prep package since 2013, are identical. hole sizes haven't changed.