Mac,
My extended safeties are all either FN MK III stype or SFS - mostly SFS.
The appearance of the SFS ambi looks almost identical to the MK III ambi because it was originally offered by FN as a factory option. It is now available from C&S as an after market kit. There is a 1911 version also.
On on both the Hi Power and 1911, it is a simple matter for an experienced gunsmith to switch back and forth between the stock and SFS configurations by fitting the appropriate parts.
Although I really like most C&S Hi Power parts, being a lefty I find that the C&S ambidextrous safety to be a torture device. I use the passenger side lever as a thumb rest. Doing this on the C&S ambi, because the passenger side lever is situated much higher and further back on the frame than the factory ambi, which requires the shooter to shoot with thumb straight up against the back of the safety and then forward at the joint onto the lever. This, especially with a HP 40, puts a lot of recoil stress on the thumb, which I find to be "uncomfortable". I had a C&S ambi on my Practical 40 and replaced it with the OEM part. If you are a righty then this isn't such an issue, since the driver's side lever is where it is supposed to be.
In the Numrich catalog, I believe that the "early style" extractor is original internal extractor used from when the Hi Power was originally introduced up until around 1964. The current, since 1964, external "standard" extractor is what you need. I generally get my HP parts direct from Bowning since Browning has better parts prices than outside vendors. I always get the extractor spring too and replace them both at the same time. They're cheap.
FN has a l o o o n g history with Argentina. Argentina purchased its first order of 1600 Hi Powers from FN in 1937. That's pre WWII for those of you who are hung over - making Argentina one of very the first Hi Power users.
FN and FM made Hi Power parts are interchangeable. FM made the FN FAL rifle and the Hi Power under license between 1969 and 1989, when FM switched to their own slightly different (mostly in the slide) versions with the M90.
FM is very VERY good at making Hi Power and FAL parts and weapons and the Argentine and Belgian companies have enjoyed a close working relationship. In fact, on a recent Outdoor Channel TV show, the NRA's Phil Schreier stated that FN had contracted FM to build FN FAL parts for their Belgian rifles.
As previously noted with the sights and grips, FM's Hi Power models have closely followed the Belgian company's design improvements.
The FM90 is roughly equivalent to the FN MKII, with a similar fixed front sight that is part of the slide and a (somewhat different) barrel rib. It does lack the MK II's ambi safety, drain hole and straight barrel ramp though.
The FM95 is equivalent to the FN MK III, while it keeps the M90's slab sided and ribbed slide, The M95 has the same dovetailed sights, ambi safety, straight barrel ramp and the same firing pin safety (FPS) used by FN on the MK III.
The M02AR is an SFS version of the M95, just as the FN SFS Hi Powers are versions of the FN MK III.
There's a gunsmith near Ft. Bragg, NC, who has done some nice work on FM Hi Powers by returning the slab slide to the traditional "Hi Power cut" profile at the front of the slide. They look really good. He's a member on this forum as "Metalmole".