ONLY 2 styles.

1957-1964 models - Red center with a styled V
1965-1970 models - Black center with a V similar to VOLVO logo

1957-1964:

Made from a chromed outer brass cap, pressed together with a metal inner cap - therefore they rust between the 2 metals and they have rarely survived the years.
Reproduction today is a polished stainless steel.
Another huge myth with the early hubcaps, are the red center - it was painted on! Nothing else! So all those NOS that comes with a red label/sticker to aply - is of course NOT NOS.

1965-1970:

Made from chromed stainless steel - In early production, the black center was painted on - later a label/sticker.
Today they are reproduced - but for the nerd - they don't really have the same nice smootheness and quality - they are a bit more *sharp* on edges etc.