Do keep in mind that anytime you want, any nylon bolt can be transformed from head style to another.

In other words, if you want the fastener you show above to be an allen key socket head, warm up the allen wrench, and carefully insert/melt a socket into the top of the screw.

Sooner or later, you're going to break a nylon screw head off, and then appreciate how easy it is to insert a hot allen wrench or common bladed screwdriver into the stub.