Bill, By rear do you mean the one under the trigger guard going to the top tang near the safety, or the short one with the big head at the front of the trigger plate?. If is is the front one Gunparts (Numrich) has it.
L.C. SMITH
NEW MODEL HAMMERLESS
Item No. 519780
Trigger Plate Screw, Front
Retail Price: $1.70
If it is the one under the trigger guard, they don't list it, but it is very close in length to the lock plate connector screw.
L.C. SMITH
NEW MODEL HAMMERLESS
Item No. 521480
Lock Plate Connector Screw
Retail Price: $3.55