Question for old Ford and Mercury enthusiasts?

I got to see a ride from my past the other day that my parents used to own. It is a 1956 Mercury Montclair. The car has a 312 Y Block engine and original 6 volt battery.

It also has a unique feature, it has a front end lubrication system that operates from a vaccum system, where if needed the driver would press a button on the dash board just above the AM radio and a little blue light on the right of the radio just slightly left of the factory clock would light up when completed.

Does anyone out there know how many of these cars were produced with this feature?

Any help would be appreciated.

L8R

AyreWolf