Do you think he remembers you? If he does remember you, chances are he will rememeber what you got. If he doesn't he might just look it up on his own. I think it's fine to reach out but again the best LOR are from those people that know you (i.e. an LOR from a music teacher that knows you trumps a LOR from a random professor who doesn't know you). What schools look for in LOR are things about your character. They dont want to hear how you got an A in their class - becuase hey, in med school everyone got an A. They want to hear what makes you so awesome) If you think this professor knows something awesome about you or that you can convey that awesomeness before May then I say go for it and its fine to reach out and say hey I took your class a while back, I did well, and now I am tutoring.So it would be fine if I said "hey, I got an A in your class two years ago, now I'm back as a tutor" give him my info (personal statement, description of activities, leadership and personal qualities, academic info, etc.) in early January and ask for a LoR, then keep in touch with him throughout the semester before he submits my rec in May - June? Would that work?