take a few pics, (with date stamp preferably... Take the pics and bow to any customs office during business hours and ask to get the items registered. Its a small 2 1/ in, by 3 or so form that you can regsiter any item (camera, puters and such...) Ask them to stamp the backs of the developed pictires with a customs date stamp and seal to carry with.
Also any optics or cameras stuff too... this should get you by the duty(tax part), but if you had an exotic or endangered species or Ivory inlays... you would still probably fall under the USFWS laws on those items...
Its a 5 min process, just call and find out where the office is and their hours... Hard to carry a bow through security to get to an office, but there is usually an office accessible by car around for clearing air freight...
A real esy deal for anything serialized and not made in the usa... watches, cameras, and if you hunt overseas, guns and bows....