Just do the G conversion. Its easy. While your at it install a Langdon Tactical trigger job in a bag. Makes a world of difference in the DA pull. Mine is about 6.5 lbs and super smooth.
Totally agree with the other recommendations for Silva. Have one for the last 40 years and managed to never break it all through Scouts and the Army. Got the job done for me all over the world.
Look at the hammer, does it actually have the "spike" of the firing pin or is it a model that uses a transfer bar? If it is the transfer bar, hold the hammer back and carefully squeeze the trigger just enough to release the hammer. Once the hammer is released, let go of the trigger so it goes...
A few years ago(2005 I think) when I lived in Charlotte someone stole a class III MP5 from a table at a gun show at the Metrolina. Place was crawling with cops at every show after that one.