I had an NOS set of chrome ‘70 E-body racing mirrors and the same deal was found. Passenger side was date coded 9 69 and no code on the driver’s side.

'70 Super Bee 440 6 pack 4-spd 4.10 Dana N96 EB5
‘70 Super Bee 440 6 pack 4-spd 3.54 Dana FC7
‘70 ‘Cuda 440+6bbl 4-spd 3.54 Dana N96 EB5 V1W