Yes there is a coolant circuit that goes through the carbs to prevent carb icing. I bypassed this when I removed the AIS gubbins several years ago with no ill effects.
/Edit: To bypass the circuit I used one of the hoses that was going to be redundant to link the connection from the thermostat housing to the connection on the radiator.
/Edit: To bypass the circuit I used one of the hoses that was going to be redundant to link the connection from the thermostat housing to the connection on the radiator.