Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1270 
GIC
ΚΟΡ in a circular punch, dots (or letters?) above
circular 
8 mm 
 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 3868 Show 3868 12 1
RPC I, 3868 Show 3868 34 1