Has anyone seen this before?

[Russell]

When I first looked at this photo, I thought that there was belt drive pulley on the rear wheel. After realizing there was no drive belt & that there was a similar setup on the front wheel. I now believe that it is a brake setup.
I am not familiar with this motorcycle and was wondering if I am correct & was this a common brake setup?

 

[MotorBicycleRacing]

Maybe having the front and rear wheel be interchangeable.
I have seen that on Vincents.