disc brakes on a 1970 longhorn

[bronze 72 super]

Just bought a '70 Longhorn with factory disc brakes!! This is not a '71 model. VIN on this is as follows: ce240z120631. This truck come out of southern Idaho. I live in North central Oregon. Brakes were not put on as a upgrade. Still have factory rivets on upper ball joints. Has anyone ever come across early setup like this? Truck will be parted out next year. Also come with a after market canopy for a 8 1/2 foot bed!! It's going on my project '71 longhorn. Any insight into this would be great.