Back in the olden days you provided your own trucks and couplers.
I always wondered why Clark didn't choose the Lionel baggage car dies for his extrusions. There never was a Budd prototype with a lower full length letterboard. Mac Shops got it close, then K-Line and GGD got it almost perfect.
But in 1980, Clark's were as close as you could get. Good luck on your proposed sale!