I have a Star Model S (1941), but I don't know if all of them have the same grips... I dropped into a place that sells replacement grips, and they seem to have several grips for the S models, maybe you can make sense from this, or check their site at
Vintage Grips
S/79 Star Model SI Pistol $18.95
S/80 Star Militar Pistol $18.95
S/81 Star CO .25 Pistol $18.95
S/82 Star Model SS (Super S) .380 Pistol $18.95
S/82a Star Model SS No Thumbrest $18.95