I think you mean OE leather boot. OE means "original equipment." It refers to either the parts the car was delivered with or to replacement parts which EXACTLY REPLACE (are 100% the same as) the original part.

OEM means "original equipment manufacturer" and refers to parts made by the SAME MANUFACTURER as the OE part which usually differ by not have the legal brand/logo markings which the OE part had, but functionally are the same.