BAT 75/150SE R2 trimpots

Does anyone know and have experience with adjusting the R2 trimpots in the BAT 75/150SE?
They are located just under the top front cover and can be seen through the slits in the "Special Edition Series" 'wing' which is easily removable. Depending on how thin and long a screwdriver you have, it may not be necessary to remove the 'wing' to access those pots.
Given their location, I imagine they are used to balance the L/R gain of the input section. They do not adjust output tube bias or general amp voltage. Those pots are accessed inside the amp.