[Neil Wilson]

AA's used A-chassis front bumper brackets for 1928-1929 as per the RGJS:

"Front bumper arms were the same as for the A chassis through December 1929. Beginning in January 1930 front bumper arms were as shown in figure 33 (attached). These arms were designed to place the bumper clamps about 3” closer together allowing either 1929 or 1930 A chassis bumpers to be used (some early 1930 AA’s used 1929 A chassis front bumpers)."

Note that starting January 1930 the bumper arms for the AA's had an AA prefixed part ID and were a different design. Using Ford Parts Price Lists shows what service parts were available at the date of the list. This does not show what was used in production.