I had the same problem with the RC timer BLDC. It is better to know before spoiling the allen screw head! Drilling this rather hard screw out of an aluminium part is an hasardous operation for who does not own a suitable tool.
I had a problem with RCtimer: the dimensions they give on their site is not at all reliable; for my motor the loverall length was suppose to be 18.5 mm and is actually 21.5. The holes on the stator are supposed to be on a 20mm circle: in fact two are, the other two are on a 16mm circle. I hope the Kv are more reliable; otherwise I am in a mess.
In fact surprisingly enough model suppliers do not seem to be very concerned with dimensions! I found three different values on a servo thickness on the same internet page: one in the description, one in the dimensions table and a third on the diagram! Difficult to build a correct design in such conditions!