Did the 1929 Buick have a synchromesh transmission?
This site says no, not until 1931.
http://forums.aaca.org/topic/113019-when-did-buick-incorporate-synchromesh-in-th eir-transmissions/
However, Cadillac had one in 1928.
https://www.hemmings.com/magazine/hcc/2015/01/Synchromesh-Gearbox/3745481.html