Hard to find!! Going Crazy

[Browns Chop Shop]

1961 Fleetside. inside the doors, under the lock and strike plate are what look like door guides. They are shaped almost triangular and bolt to door with two bolts. There is a matching guide slot in jam of door. looks to help guid door and keep from sagging, I have lost the drivers side!!!!! Checked with every parts house I can think of, no avail..........