A quick thumb through of Grinslade's book shows the following guns ID'd as New England fowling guns show upper and/or lower foestock mouldings on #'s 11, 14, 15, 18, 19, 26, 27, 29, 30, 31, 34, 40, 45, 52, 53, 54. Seems a common feature, at least in this sampling of NE fowling guns.
This shows influence from French trade guns which commonly had upper and lower forestock mouldings as well.