Countermark

https://rpc.ashmus.ox.ac.uk/countermark/519 
GIC 397
circle, incuse, with incuse dot in centre
On reverse 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC IV, 6606 (temporary) Show 2799 1 4.3
RPC IV, 6608 (temporary) Show 2798 1 4.3
RPC IV, 6607 (temporary) Show 2796 1 4.3
RPC IV, 6729 (temporary) Show 2877 2 4.3