I've seen that head marking before. It may have been on some AMK bolts, maybe fuel pump bolts or it could have been license plate screws. Cannot be certain and I have no idea about originality or when used if they aren't. Have an older AMK catalog, 2005, that has a page in front with various logos (the ELH is there), but that marking is not present. Hopefully, someone else can weigh in with more knowledge.