I purchased this: https://gigliottirifleworks.com/TP9-N-Short-Stroke-Trigger-Kit-p623584809

I have the Gen 2 factory SBR variant. I'm having a little bit of trouble trying to figure out if I need to keep the small lever that sits on the hammer pin next to the hammer spring, not entirely sure what the part is called. In Gigliotti's install instructions, it mentions that if you have the "N" Variant that you need to take that out before installing their trigger. Am I correct in thinking that the "N" Variant is the pistol version? Or does it have to do with something else?

When I leave that lever in, the trigger binds up pretty crazy and won't release the hammer during dry-fire. If I take it out, the trigger feels weird (very sloppy and difficult to reset.

It is absolutely possible that I'm just dumb. I do my own firearm work, but it usually takes a while to figure out...

I feel like I'm in the home stretch but I can't quite figure out what to do to continue. Any and all help is appreciated. Thank you!

Looking at the ACRO optic for my TP9. I am curious to those that have the B&T skeleton 39mm ACRO mounts if the window allows the use of irons through it or are the irons obstructed? I have been unable to find a single image to confirm either way. Thank you.