Oh god, not this again...
V42, You can still get the J+ style front guards from Yamaha - they're fairly similar to the original G/H guards. Fairly cheap too.
You can get 250K+ rear guards from Yamaha too - maybe they fit the earlier 125? Be worth looking into, for a race bike.
VMX Plastics/Concourse Parts are/were planning on doing G/H plastics. You can join me in holding me breath for them, if you want...