Collecting the Boston Store set is a tall order and I wish you luck. There are 3 HOF rookies that are all tough (Rice, Heilmann, Hornsby). I still don't have a Hornsby.The M101-5/4 are disctinctly different from the family of Boston Store 801-8, Weil Bakery D350-2, Collins McCarthy E135, or Standard Biscuit D328. The M101-5/4s are shorter and narrower.It does get a bit confusing since there is a Standard Biscuit (D350-1) back which overlaps with the M101-5 checklist (same fronts) and a Weil Baking (D329) back which overlaps with the M101-4 checklist (same fronts). I don't think the Standard Biscuit was produced in the M101-4 print series but I could be wrong.This is one of my favorite cards. It shows the early print cycle (m101-5) indicating him as a pitcher: This is my absolute favorite family of cards (still need the Collins McCarthy):