I'm confused? Rule "k" is already in the latest rule book. The point is obvious, you can cover the fog light openings... Whatever GCR you are looking at must be out of date.
first rule is concerning the part.. Rule say is must be the same basically.. One with out fog light provisions is not the same.
So even though you must cover the opening... the part is not compliant unless written into the rule
GCR 188.8.131.52.c: The “R” package Miata chin spoiler is allowed on 1990-1997 cars provided it is mounted in the OEM location. 1999-up cars may use the OEM chin spoiler for these cars (99-00 p/n: NC10-V4-900F or 01-05 p/n: NO67-V4-900G). Aftermarket chin spoilers may be used but must use the same mounting holes, must have the same dimensions and must perform only the same functions as the OEM chin spoiler. Fog light holes may be blocked over in reproduction spoilers. Any material may be used.