BOAC:
Depends how they are 'published' does it not?
If they appear in the AIP they are public and for everyone's use, subject to approach category limitations.
There is also a provision, not used by all ICAO member states, to issue non-public procedures to sponsoring carriers, but that is a very limited process.
If you are implying "cocktail napkin" procedures those are usually not flown in IMC in radar airspace, and especially not by air carriers.