With all due respect, do you honestly believe that submitting an FP LOR instead of a Medicine LOR is going to be "THE" determining factor on where you go???? In the grand scheme of boards, grades, honors, research, etc....IMHO it doesn't make a hell of beans difference. As long as the rec is strong and shows that you are a hard-working, personable individual even outside of anesthesia means that it is worth submitting. Hope this helps and good luck! 🙂