Identify Seat Track Runners ?

[Ironhorse]

Needing some assistance to identify these seat track runners I acquired some time back. Came in a box of parts that were from a 68-69 short bed Chevrolet pickup. Truck was on a 4x4 frame but don't know if it was an original factory set up or a body and frame mix. Runner channels measure 14'' long with the taller threaded stud 2 3/4'' tall, short stud is 3/4'' tall. 5/16 x 24 fine thread on both studs. The seat track runner with the adjustment handle is stamped with an A along an upside down V, then a straight bar or line under the two letters. Below and to the right of that stamping is the numbers 14117. Tried to show in the pic but hard to see. Really stumped on this, have not seen these before. Hope some one can help me out on this.