I believe Boeing certified a CAT IIIa capable HGS on its 737 at the beginning of the 90ies with the first airlines equipping them around 95. Apparently the HGS is still preferred over a CAT IIIb capable autoland system in the US on the 737. Apparently they test flew Jurassic 737s with HUDs since the end of the 70s which ties in with the timeline clandestino mentioned.
The restriction clandestino mentions must be imposed either by his company or local CAA, on the 737s (CAT IIIb) i flew and the A320 i still fly, manual CAT II landings are allowed without the use of a HUD. However, autoland is preferred of course.