The several 49-53 generators I’ve handled have two ¼” locating holes. The rear hole works for my setup which is a single, wide-belt on a V8. What is the front hole for? The dual, narrow-belt setup or maybe a 6-cylinder?
I use the front hole on my 1951 6 cylinder with the narrow pulley/belt.
Here is a 2-hole 8ba narrow belt generator on my bench for restoration.