Yes they are. So bolts with round heads is not the issue as all such allen bolts have round heads. It appears that someone does not have the right tool. But he does indicate they have been rounded out, but that is rare on high tensile bolts.Are the starter motor bolts not allen bolts with round heads?
I distinctly remember cutting a 10mm allen key to make a stud i could get a C-wrench on to take off my starter on top of a mountain