Since you're in Jersey, Mandolin Brothers (on Staten island) is right up there with Gruhn's as far as reputation and integrity. Plus, owner Stan Jay is one of the nicest and funniest guys you'll ever talk to in the guitar biz.
http://www.mandoweb.com
A quote from their website;
Widely known as one of the largest dealers in the world of vintage and new American fretted instruments, we are frequently recommended by Gibson Guitar Corp., Nashville, TN, when they receive inquiries about vintage and used instruments. We have appraised the contents of the CF Martin museum for Martin five times, the estate of CF Martin III, and the personal collection of George Fullerton. We are recommended by many local music stores around the country and by other manufacturers, libraries, museums, magazines and newspaper columnists. In business since 1971, we service the needs of over 225,000 players and collectors of American fretted instruments.