For a USA LHD 1970 bus, there is only ONE master cylinder: 211 622 021T

This master only has one brake light switch.

68-69 USA buses use the 211 611 021Q master.
68-70 masters are not interchangeable with 71 and up.

The center-to-center measurement of the reservoir nipples are 100mm. 67 bus and 71 up are 85mm, same as Volvo, Rabbits, and Mercedes.