My suspicion is "no", based on the existence of this Loremaster feat, Quick Study:
During your daily preparations, you can study a particular subject to gain the trained proficiency rank in one Lore skill of your choice. You must have interacted with that subject in some way on the previous day, whether by reading about it, talking to someone knowledgeable on the topic, or experiencing it yourself. Alternatively, you can reference your notes to instead choose a Lore skill you've prepared before with Quick Study. This proficiency lasts until you prepare again. Since this proficiency is temporary, you can't use it as a prerequisite for a skill increase or a permanent character option like a feat.
If the narrower lore skill wasn't beneficial in some way, then this would be strictly worse than Loremaster Lore.
I welcome other's thoughts though.