I think if you said you have both, and handed them an FID, I think you'd have a bigger problem then buying ammo. Unless you felt it necessary to pay $100 to the Mass government for a lesser copy of your LTC.
Unless you're under the age of 21 and over the age of 18. You could be thinking that you were going to be shooting with your dad's .22 pistol as well as your rifle while you were both at the range.