from a 1935 chilton
Audburn lists bronze backed main bearings---renewable from below
Cadillac --bronze backed --renewable from below---by 1930 steel backed for some
Chyrsler 75, 28-29, bronze backed, pull engine, but no hand fitting or reaming
Durant 1929 --pull engine but no fitting or reaming
Grahm paige --renewable from below
Oldsmobile f33 1933 --mains, steel backed, renewable from below, rods removable babbitt lined steel shells
Nash 1220,(1934) mains, steel backed, renewable from below, rods, removeable steel backed babbitt lined shells
Hupmobile, 6 cylinder 1934, mains bronze backed, removable from below, rods, removable steel backed babbitt
I remember taking apart a Franklin engine and it had a form of inserts, it was before 1928, to me they seemed like solid babbitt ---but they had the look like they required fitting , the cars that list "renewable from below" to me indicate modern style precision fitted bearing inserts, but although I didn't look up all the cars it seems that modern type steel backed precision inserts appeared in 1933- 1934 in several cars for rods, mains before them