"Sic et non" ("Yes and no"), to quote the title of the most famous work of the old school French philosopher and theologian Pierre Abélard (sadly, better known for his unfortunate relationship with Héloïse d'Argenteuil).
Which parts for which MAB pistols?
MAB pistol models include the models A, B, C, C/D, D, E, F, G, GZ, R (in several very different variations and calibers), PA-8, PA-15, and PAP-F1, with calibers ranging from .22short to 9mm parabellum. The F and R-22 target pistols came in a variety of barrel lengths, as well as both .22short and .22LR. Most MAB models underwent design revisions, minor and/or major, during their manufacturing years, which affects parts availability, and some models and versions are considered rare.
The easiest model to find dealer parts for is the model D in 7.65mm (.32ACP), especially those made after 1945 (ie, the Type II pistol); most of the parts are the same for the much less common 9mm short (.380ACP) model D. Most parts specific to the Type I model D can also be obtained.
The alloy-framed model GZ, most of which were made in Spain by the Eibar gunmaker Echeva (as "MAB Espanola") during the 1960s, is also generally easy to find parts for, although, again, the caliber of the pistol is a factor (these came in .22LR, 6.35mm/.25ACP, 7.65mm/.32ACP, and 9mm short/.380ACP). This same pistol, in the same calibers, was also sold by Echeva under several other names.
The PA-15 can still be bought new, custom built by a well-known French gunsmith who has the remaining MAB factory parts, although the price is high and getting one from France to the US might be difficult or at least expensive.
Good places to start looking for parts are Numrich (www.gunpartscorp.com), Bob's Gun Parts (www.gun-parts.com), and Springfield Sporters (www.ssporters.com/parts). With all of these, it is best if you know exactly what part(s) you want for which version of a model, since none of them are experts about MABs and you may get an earlier or later part than you need, as well as occasionally a part for a different model. Replacement model D springs are best obtained from Wolff Gunsprings (www.gunsprings.com).
The advantage of online auctions is that you generally get to see photos of exactly what you are bidding on, although sometimes the seller has an exaulted notion of the value of a part.
BTW, MAB also made flare pistols, but these and their parts should be regarded as hard to find anywhere and unobtainable in the US.