The bar seems to be with one's that claim to be original 1928 (early 1929). But the pivots in the seat and floor have me confused.
One of my seats have a bar and the later pivot setup and the other someone mounted some more modern seat tracks. So either I find cups for both seats or a bar for the one that's missing.
To add more to the mystery:
https://www.fordbarn.com/forum/showthread.php?t=286862