Yes, in case you roll 1 Success + 1 Aim at least. If this happens, you can allocate the Aim to the Success which gives you an extra hit (you are now at 2 hits).
Then, if you did this with the Shotgun, the Aim converted to a hit, so your total hit will be 3.
I do not see anything in the rules which would prohibit this to happen, it sounds like valid.
Deadeye: Each aim allocated to a success in an attack roll provides an extra hit (as well as providing extra range)