Bushing / water seal between two meters

[byteharmony]

I need two meters right next to each other.

Do I need a rubber seal between them and then a nipple pipe that squeezes both panels together? (Like below)

 

[timselectric]

It depends on the location of the nipple in relation to the live parts in the equipment.
If below the live parts, no weather seal is required.
If at or above, then the seal is required.
There's no code compliant way for them to be against each other. A Meyers hub (two in this case) is the correct way.