The AAS is one of those amazing but somewhat little know repositories of amazing stuff.
Though I have not done any watch related searches, some other organizations that are places I have searched for and found great information about everything from furniture to lithographs to silhouettes to glass and so on are the Boston Athenaeum, Historic New England (previously called Society for the Preservation of New England Antiquities, SPNEA; they maintain some wonderful historic homes you can visit, too),The Boston Public Library and the MFA, Boston. It's amazing what resources are available at your finger tips...if you're curious and at all motivated.
A portion of the AAS collection came from the estate of Samuel A. Bemis who repaired watches in Boston 1812 - 1822 before he decided to become a dentist. He worked for John McFarland and later Baldwin & Jones.
The Henry Ford Museum has two of his watch repair account books as well as his father's Samuel Bemis account book. They are fascinating to look at.
I have a pictorial database of several thousand American watch papers and other papers from the U.K. and Canada. Much of the information printed and written on the reverse is useful to researches. Glad to provide information to any member. This is a photo of what we believe is the earliest surviving American watch paper that was located in a colonial watch by the same maker/retailer, Samuel Bagnall of Boston, circa 1740.