Hi Bruce

No answers but you have got me curious.
Only familiar with later 12v models but these have field coils with flat bars not conducive to rewinding. Field in series with armature, but the NSNS fields are paired in series then if two brushes both tails connected to the same brush, and if 4 brush connected to opposites (which are the same electrically) so still in parallel. The fields conceivably could be each in series or all in parallel, then in series thru the armature. But I guess you know all that... I understand starters exist with alternate poles not wound...
If the windings have many turns perhaps were connected in parallel as the dynamo?
Someone must have a starter apart!

Location: Auckland, NZ