Update for mine...
I decided to remove the so-called mag "safety" on mine after posting to this thread. Some yahoo has a "MkIII Mag safety Removal Demo" on Youtube (a hideous SS BHP with gold trigger). Whatever dude is doing, does NOT work at all.
In order to remove the safety on the FN IDF MkIII, you have to remove the roll pin on the trigger (as shown in the video), but then you must disengage the entire trigger housing via the main trigger roll pin in order to dislodge the mag safety. I tried this yahoo's methods for 30 min, jabbing and prying with an awl and screwdriver before giving up and dropping the trigger assembly out. This was extremely simple. it takes a little shifting around to put everything back in but I did this on instinct without instructions. There are only 2 roll pins and 3 parts to contend with once the safety catch and spring of the mag "safety go flying out"
When I re-assembled it, the trigger was very gritty and hesitant with the re-set. This was after cleaning with naptha (lighter fluid). Then again, I was wrenching and prying like a SOB with brute force in foolish reliance on that bad video, so there may have been a little unnecessary bending or shifting that otherwise won't take place. After some generous lubrication and some manual manipulation of parts, the reset sprang back to reliable function.
That said, I would agree that reset does not appear as robust as it was pre-removal (a known symptom of the removal) However, the nasty, gritty trigger is gone leaving that single action revolver/1911 smooth break that is night and day different from its original characteristics.