I guess it sort of depends on what you think the real number two is. Injun Joe tells his accomplice that they should hide the money at Number Two, under the cross. So to me, that means wherever the money is hidden is Number 2 even if it doesn't have a number on it.
What the boys think is that it must be room #2 at one of the town's two taverns. But one of them is occupied a perfectly respectable young lawyer and the other one turns out to be a room where whiskey is being sold secretly.
Where the money is really hidden is in the cave. So I would say that makes it the real number 2 even though Injun Joe and his accomplice do drink at the number 2 where liquor is sold.