Here. This may shed some light on the subject for you.
Top to bottom,.....
#1, 1928-1931 Model A
#2, 1932-Only (Pass. and truck this was NOT commerical only)
#3, 1933-1936
#4, 1937 (early38) "Tubular" ( from V-8 60hp only)
#5, 1937-1941
#6, 1942-1947
#7, 1948 only ( extra hole for shock mount)
As you can see in the pictures the spacing for the wishbone boss got wider in 1937. The spring was first mounted in front of the Axle in 1935.
Still a good axle to use, so don't be too discouraged.
BTW, remember when computers used to be huge? Gastrick must have one that takes up a whole room. He can come up with virtually any picture or chart in like 30 seconds. lol