Captain Bishop,
I am no expert but according to what I am seeing in Steffan's books the two brass sliders at S & S Firearms in New York will work on both the webbed and leather belts of the time period.
Go to their site, click on the 2007 "Navy, Marine, Artillery, Cavalry" catalog, scroll down a few pages and its picture is #50 and it is item # HS50 in the listings.
I bought the set today, they are instock.
Send me your address and I'll send you the sabre hanger, no charge.
Email me direct at rancidroy@prodigy.net.
Regards, R. R.