1936 3 Window Coupe Seat Base

[hrs1948]

In my search for an original seat I have looked at a number of posts / threads and there appears to be a couple of versions of the steel base. One type has a center front-to-back brace, the other does not have this brace. Otherwise the bases seem to be identical. Are they both original for 1936? Is the one without the brace possibly an early version and the other a later update / improvement? Thanks!