I was sent a photo of an SP1 lower with a ‘shaved’ magazine well. The owner asked if I knew why the magazine well was like that. I had not seen one before and was curious to learn more. If you look below the rollmark and to the right of the rollmark, you can see the line showing how much material was ‘shaved’ off or removed.

I posted an inquiry in my Facebook group and had some private message conversations which were interesting. I learned that when a mistake was made in the rollmark process or when adding the serial number (double print of a serial # for example), the factory would remove as much material as needed and then repeat the rollmark process or redo the serial number.
Anyway, I thought I would share this here so thatbothers can learn from it.