Conversions from Single Trigger to Double trigger have been discussed on the board a few times in the past.
The switch can be accomplished on a basic level by just swapping out parts which results in the function of double triggers, but leaves evidence of the former single trigger on the trigger plate.
This is fine for most guns as heavy modification on the outside is not wanted by most owners. However, if you want to leave no evidence of the conversion having been done, you have to do things the hard way...
The pictured gun is a Repro A-1 in the white. I tig welded up anything related to the single trigger. The long trigger slot was filled in with a cut off piece from another trigger out of the parts bin and then welded. Everything was dressed down and polished out leaving the gun ready for double triggers.
Obviously the same applies to original Parker guns as well. Not just repros.
Trigger plate before.jpeg
IMG_2644.jpeg
IMG_2646.jpeg