Linda, I have seen it in some of the family trees posted by either the Society of Dames of Va or DAR (that Richard was the s/o Sir Robert and Lady Grace Talbott) as recognized data. Other places have Richard a cousin who married Frances d/o Sir Robert and Grace. However, the other material I have seen shows Sir Robert Talbott and Lady Grace Calvert to have three children; Frances, William and George. The Richard that married Frances stayed in Ireland and had a son Richard born 1668 well after this Richard was in the colonies. The Mayflower assn. has this Richard a pilgrim that emmigrated to Va. Lady Grace Talbott had a sister Dorothy that marrieda James Talbott. I haven't found info on their children yet.
So, I have not found conclusive evidence in any direction. I know it doesn't help but for what it's worth.