Help with 3 Indian Punchmark Coins

It seems the first two coins might be Series VIb (based on the Gupta and Hardaker book), but where would these go in the numista catalog? Most of the Mauryan punchmark coins have no reference with them. Top left coin is 3.06 grams and 16 mm, top right is 3.11 grams and 12 mm.

The bottom coin looks like it might have an Om symbol which I have not been able to find on any punchmark coins. Does anyone know the ID for this one? 1.75 grams and 15x13 mm

I think the first one could be from mauryan Era and the second from shunga and third from pre maurya based on he typical punch marks I see..though the coins have little detail left..this is my best guess I don't think there would be any om symbol these. Numista has to really improve on ancient and medival coins...he catalogue is not good in these areas...

Quote: "Meet"​I think the first one could be from mauryan Era and the second from shunga and third from pre maurya based on he typical punch marks I see..though the coins have little detail left..this is my best guess I don't think there would be any om symbol these. Numista has to really improve on ancient and medival coins...he catalogue is not good in these areas...

​Thank you!