Looking for Customhouse Records from Portland, Maine ca. 1839-1845

Hi Everyone --

I'm interested in finding the "crew list" for a vessel that shipped out of Portland, Maine in the early 1840s.  I understand that there was a US law that required all ships on foreign voyages to register their crew with the customhouse.  The NARA catalog (Record Group 36.3.1) indicates that these records could be in the regional archive (Waltham, MA) or in Washington. 

Could anyone verify the location of these records?  Also, might there be a list of vessels who filed crew lists? (wishful thinking, I know).

Thanks!

Martha McNamara

Wellesley College