BudsGunShop.com - Magazine Disconnect for Beretta 84FS (or 85FS)

Item# 25974 appears to be what you want. I read and re-read the manual just now. And the magazine disconnect on this model was ONLY AVAILABLE on request. So I think this is it. I would double check before ordering, but I think this is the one you're looking for.

Copy and paste this- calguns.net/calgunforum/showthread.php?t=398344 (this has a link that let's you download the manual. It has info on like page 5 for the 84F series.

They will all have this from the factory Derek. But 2 minutes as info only : youtube.com/watch?v=3eJholO43kw

Base versions of models 81 through 87 are noted for having a rounded trigger guard and generally fewer safety features than subsequent versions. Safety is ambidextrous and frame-mounted. The frame is alloy, the slide is blued steel and the standard grips are wood. So the FS models will not likely meet your needs. A standard Cheetah may be your best place to start looking. If you see any suffix, it probably has that safety.

No you can't