Should I be able to...?
You don't state what stage you're at post operatively? I still can't eat soft bread or lettuce and I was banded 7 1/2 weeks ago. I am absolutely not hungry, although the mental urge to eat is certainly an issue. Your band is not a magic band but a tool to assist you in losing weight. Ask your surgeon if you should be eating that much and just because you can doesn't mean you should. Still coping with that myself. Good luck to us all!!
When did you get your band? I truly don't think a sandwich is the best choice and a true test of rather you need a fill. A sandwich does not offer that much dense protein. And you could be one of those who can eat bread without a problem. If you want to test to see if you are getting hungry within the 3 hours...Dense Protein, and veggie, not to mention bread really does not have any nutrient value.
You could ask for the meat and all the toppings for the sandwich, without the bread...I do this a lot. I also will order fish tacos if we are out at a restaurant that does a good one, and eat everything except the tortillas. Keeping the carb intake down is a good idea to get the scale moving...and with bread you could find yourself stuck and miserable.