When placed next to other
unique sets of the Indian Palace buildings, they give extra rewards.
The numbers 1 and 2 you see are showing you what extra rewards you would get if the building is next to those numbers of unique buildings belonging to the same building set.
This screenshot from mine, which is already next to two other unique buildings from the same set:
1) The coins you will get when you collect from the building.
2) The extra coins you will get because the building is next to another unique piece of the Indian Palace set.
3) The Forge point you will collect because the building is next to two unique pieces of the Indian Palace set.
More info including what the other buildings in the set are:
forgeofempires.wikia.com/wiki/2017_Summer_Event