No dealer likely has them.
You need to spend some time on a parts fishe and order them. (a whole collection of bitty parts)
They are not Interstate hinges, they are cable ties that allow the lids to lay over on the side of the bag.
There are two ties per bag, and the hinges are replaced by clips.
http://www.servicehondapsn.com/fiche_section_detail.asp?section=4224016&category=Motorcycles&make=Honda&year=1999&fveh=188145#55, 28, 26, 52, 42, 30, 16, 29, 49, 41, 25, 2, 27 and maybe some others (2 or 4 of everything). Fishe is hard to follow. It would be helpful if you could find an interstate to look at the lids and mounts with a xerox copy of the parts fishe in hand.
The interstate bag lids also have side legs to hold the lids off the bags when laid over on the side (paint protection) (19, 20 and hardware). If you have bag rails or are careful, you don't really need the legs.
As the interstate was rushed to market in '99, the hinged tourer lids were discovered to be a problem with the trunk as you have found, and this cobbled-together deal was the solution.

Which reminds me, I need a new #26 myself.