Hello! I have done extensive customizing on FEG Hi-Powers, and found that MOST parts are fully interchangeable with the Brownings, although virtually ANY aftermarket parts will require some degree of fitting. If a Browning fits your girlfriend's hand well, so will the FEG. External dimensions of the FEG match Browning's virtually identically. I own 2 of these clones; one is a full-house custom, and the other is a lightly massaged carry gun. Both Novak, and Cylinder & Slide extended safeties fit, but require a bit of finesse to install. I prefer the C&S safety. Hogue rubber finger-groove grips drop right on, but if you want wood grip panels, some brands may require fitting. My Navidrex Dymondwood grips certainly did. If possible, try them in the store before you buy. The .285 in. rear sight dovetail dimensions match Brownings (I installed a Mec-Gar adjustable rear sight on my custom). Federal Arms barrels (among other brands) will drop in, but require a ton of chamber work to function reliably, as the FEG chambers are a bit oversized. The FEG's factory barrel provides quite acceptable accuracy, anyway. I just wanted a ported barrel on the custom, and don't regret the time it took me to get it to work well. At 15 yards it shoots 1 hole groups on my lucky days
Internal parts look like they should interchange also, and I'm sure at some point I will install a C&S hammer/sear set. By the way, a trigger job for this gun is a MUST. My carry gun breaks cleanly at 4.5 pounds with the well-polished magazine disconnect safety in place. This clone is an excellent value, and quite reliable with all of the ammunition types I've tried (including hollow-point rounds); you won't regret your purchase. Good Luck & Take Care- Dakotan