In other places, its clear from the context the gd. means grand - at least if they're being consistent.
Also, wanted to add, in the Kendall Genealogy when they say John Kendall died in Cambridge in 1660, its unclear what they mean, as there was a John Kendall who died in Cambridge, Massachusetts in 1660. Maybe they are swapping facts around...but having that date in print has certainly added to the confusion.