BAengineer,
Many thanks, you are indeed correct.
Upon a bit of further investigation I have been led to believe that the AoA sensors are calibrated at the factory and are interchangeable between L/R and attach directly onto the fuselage with screws and can't be misaligned. The respective sensor vane has a resolver/s attached to it (internally) and sends an electrical signal to the SMYD's (SMYD1 for L(Capt) and SMYD2 for R(F/O)) which alerts the respective SMYD as to what position (L/R) the AoA sensor is in (vane has to move through 180deg when swapped from L to R or R to L positions). The respective SMYD's then recalibrate vane angle and transmit to Capt/FO screens.
There is a ground test function on the SMYD's for AoA sensor test/chk, but as you mentioned NOT mandatory upon installation which I find rather odd. This info pertains to the B738 and I would assume (very dangerous in aviation) that the MAX would be similar if not the same.
Rgds McHale.