Yes, because "universal" plates are for universal PCBs. Holes are also enlarged for fitting PCB-mounted stabilisers for the Space Bar, left and right Shift, Enter and Backspace. Most 60% plates were made to be compatible with Poker - which was a PCB-mounted keyboard.
Those plates also don't extend outside the dimensions of the PCB - they are actually suspended by the switches. The purpose of those plates is mostly to alter the feel, for bling and for extra protection against things that could fall in-between the keys.
The best solution would be to ... eh.. buy a GH60 PCB.
You could fill gaps with pieces of aluminium, backed with pieces of aluminium glued with extra strong epoxy but that would be only to keep the switches from sliding and would not support the "\ | " key or any plate-mounted stabilisers very well... and you would need to do this in several places so it could be a lot of fiddly work to fit everything in. (unless you have access to a CNC router or plasma cutter, but then you would better have made a new complete plate from the beginning ...)