The 1722 D.G. REX Rosa Americana Halfpenny is a scarce variant that features an abbreviation of the legend "DEI GRATIA REX." Breen called this a prototype, which may be the case because there is only one D.G. REX variety and there are many DEI GRATIA REX varieties.
Building a Condition Census for the D.G. REX variety has been an interesting challenge because none has been attempted before. We have uncovered at least a dozen Mint State examples, though there are no Gems among them. The best examples appear to be a pair of PCGS MS63's, but the three Mint State examples from the Ford sales may be contenders, as well.
For in-depth information on this series, see Syd Martin's 2011 book, "The Rosa Americana Coinage of William Wood."