https://rpc.ashmus.ox.ac.uk/countermark/1719 

GIC —

branch in rectangular punch

rectangular 

6 x 3 mm 

Uncertain (Uncertain)

The two given examples are on coins of a) Alexandria in Troas and b) Apamea in Phrygia. The puch size id the same and it is applied in the same place on the coin, bot 19 mm in diameter. It is not certain, however, that it is the same cmk.