Casement window operator details

I have oldish metal casement windows (installed in the mid 1980's) and would like to replace the operators. Your Getty 39-045 9" Operator arms look like they may work but I need to know details about it. Specifically, is the back of the operator arm where the round disc on the end is attached flush with the operator arm or is there a low profile rivet there? The operators I have are flush here and, if there is even a very low profile rivet on the back side of the operator arm, the windows will not fully close.

Thanks.
Rick