3B doesn't have the three small panels at the bottom, with the center one hinged to open on a 3A.(M38 used the same panel but bolted it shut..) It is shorter in that area too, to make up for the higher cowl.
The DJ used both the 3A and 3B style windshields, depending on what was ordered, The sporty convertible model normally used the 3B frame. The Surrey used the higher frame which raised the top a bit �for more room.
