The trigger on the left is the earlier type with the extra hole. This hole was used as an index piont on
the manufacturing of this part. All cuts were made referenced to the hole. Very early triggers were marked with
a drawing number C-46020 and then revisions on the number through -5. C-46020-1, C-46020-2 etc.
The trigger on the right is the later type 2 trigger used throughout most of Springfields production.