The two holes are normal . That 3rd hole I know Transgo don't drill it . Other kits do. What that is is a restriction feed at the 2-3 backout valve . Transgo keep that operational with the white spring.well maybe its the instructions i have. in your picture you show 3 holes and in the transgo there are only 2
Drilling that extra hole does away with the restriction and usually use a ball or machined plug to block all movement of the 2-3 Backout .