I understood that you were not sure, i'm also not.
What i'm sure, is that it's not a Citrus hystrix, because we never buyed a kaffir lime fruit, and the leaves don't smell like Citrus hystrix leaves. They have a very faint smell, but I could not describe it.
But if it could be a hybrid with a pomelo and a kaffir lime, how would the leaves smell ? would they have hairs or not ? and would the new leaves have anthocyanin or not ?
Now i'm not sure anymore...
I think that i'll have to wait some more years for the fruits, as it is only 4 years old.