As mentioned above, most MX-family stocks will bolt up without too much of an issue be it a Type II, III, or IV. Where it get's interesting is in the forearm selection per MX Type, and even per generation in Type IV. Barrel lug Type and location will dictate which forearm iron is compatible with which type of forearm wood. (that's when the addiction starts, LOL!) There a several knowledgeable Perazzi experts on here like Steve W, JACK, and more who offer lots of advice, plus the archives have tons of info.
Also, there's several competent gunsmith's who can modify wood/metal to accept new stocks or barrels also.