Current production Thunder 380 single stack 7 round magazines fit Models 83, 95, & Thunder 380.  These have 6 witness holes on the side.

The model  383A uses a single stack  "square" face (with rounded corners) magazine like the current production Thunder 380 7 round mag.
These have six witness holes on the side or three witness slots on the back.

The model 383DA uses a single stack round faced (half circle) mag with an upper right side latch slot and a lower right side mag safety "bump". 
These have three witness slots in the back.  (Very hard to find)

The Early models 383 and 97 use a single stack round face (half circle) mag with a lower right side latch slot, and no mag safety feature.  No witness holes on the side.
These have three witness slots in the back.  (Difficult to find)

The models 85 and 86 are a 12 shot double stack magazine. (Very Hard to find)

The Thunder Plus is a 15 shot doubel stack magazine. Will also fit the Models 85 and 86 with  modification.