Are Ogres allowed to become Priests of Vaprak?

The Complete Book of Humanoids allows for PC Ogres with a level limit of 3 in Shaman and no other divine spellcasting class allowed.

Monster Mythology provides details for Vaprak’s (the god of Ogres) priesthood, with a level limit of 3 for Shamans and a level limit of 7 for Speciality Priests.

My understanding of Specialty Priests is they are something that can be taken instead of Cleric. Is my understanding of Specialty Priests flawed or is there something else RAW that addresses this?

Monster Mythology additionally states in the intro that other races can become a Specialty Priest for any given god, but if they are not the god’s race they have the same level limit as the Shaman. It seems clear the intention was to allow Ogres to get to level 7 Priests under Vaprak, which is how I’m ruling it in my game, but I’m hoping to find something RAW to further justify that decision.