You need to have a foundation before you can build a house. You need a foundation (MCAT, GPA) before you can build an application (LORs, Experiences, Interview). However, if you mean low as in lower than average but not non-competitively low or low as in a bit low but with some really extenuating circumstance, yes I think it can help. When you say strong LOR I assume you mean strong in content and a good author. The author is most important and yes if that author is an alumnus or faculty of the school then I think it is even better.