Well Rory,you could have an ultra rare jug here my friend.Everything looks good to me let me know if you want to sell it or trade up anything.I do not have a bottle from Marshalls glass works.The following from the book The Glass Gaffers of New Jersey and their creations from 1739 to present.
That is not quite it Steve, but close. This one is more of a globular form, like a softball, and the one you point out is elongated.
I am pretty confident that this is not a Stanger piece, but rather an 1840-1860 piece, and either Jersey area or Baltimore. There are some examples in amber that were produced in New England, and also in the Midwest.