Just looking through the parts book I see:
48-52 Comm (3 speed)(exc. 1 ton) 3695051
50-54 1/2, 3/4 ton (3 speed 0 9exc. sub 03698173
50-51 1/2, 3/4 ton (4 speed)(exc sub) and
52-54 comm. (4 speed)(exc. sub) 3698181
54 comm (exc sub, ffc) 3709643
Is it possible that the extra studs came on 4 speed trucks? It makes some sense as the shifters would tend to move the floormats.
