That looks like the one inline tube sells. Is that original and just really cleaned up, or from Inline tube? Or from somewhere else (and if so, can you tell me from where?)
It's an original one that i just cleaned up using a wire scratch brush.
When i find 72 and earlier disc brake cars for the Kelsey Hayes disc brakes, that i rebuild, then put up for sale, i always get the proportioning valve and lines also.
All the ones from 72 and earlier that i have gotten off cars are like that one pictured.
Pretty sure that one came off a 71 or 72, with all the components that i have currently on e Bay.