Interesting speculation in that first link above.
The center cap with the pointed middle never was released for production. ALL wheels used the same slightly raised center, including the Darts and Barracudas. Parts books list the '130' part number for both large & small b.c.
The fact is that Kelsey did keep making the wheels with chromed outer rims because Chrysler owned the trim ring. That trim ring was only used on the cast road wheel, hence extremely rare to find today. Guys will use C body rings instead, but they don't have the proper curve to look correct.
Also - the Kelsey specific released wheels, made after late August,1968, have 10 rivets instead of 15, holding the cast section to the outer rim, unlike the OEM MoPar wheels. I'd think the OEM ones would have met more stringent standards, because of those 5 extra rivets.