I don't know about the Thunder .380 and the 95, but I know model 383 and 83 magazines aren't directly interchangeable (slide stop cutout on the left side of the magazine is lower in the 383, I think).
Bersas are great guns, but I wish I could find a pair of slimline grips. The bulky grips feel great in your hand, but add a lot of width that makes it much harder to conceal. I'm considering buying a second set of grips from Eagle Imports and sanding them down to a slimmer profile.