Great entries Glen and good observations, the heraldic mullet idea makes pretty good sense, and it seems quite possible the lozenge might associate with makers marks or perhaps even hallmarks.
I think with these officers swords in this period there was a great deal of rather subtle symbolism employed in these designs, but of course most of these kinds of things were rather arcane in contemporary social protocol but not really recorded for posterity.
Jeff, excellent references and its great to have you in discussion here, its been a while!!!
Thanks very much guys!!
All the best,
* just recalled that the mullet in heraldry is a star, not a diamond