I checked, and my original belts are also black -- just a little faded. The ebay belts are the 3-point lap and shoulder kind.
I like the idea of replicas, since they should be easier to install. I believe that retractables require another hole (a total of 4 (3 for retractor and bracket), compared to the original's 2+1). The extra hole may be located somewhere in the back under the removable platform (as far as I can tell from the previous posts).
Previous posters believe that if adjusted properly, the original 3-point Kangol's should be as safe as retractables.
Also, when buying retractables, make sure that the receptacle end is short enough to just come up to the side of the seat. I made the mistake of buying a "guaranteed fit" retractable from an outfit who wouldn't take them back (the receptacle was too long, it sits over my kidney).
I found another site,
http://store.gotbelts.com/style.html -- who will to do a retractable in choice of color and length. They offer either 110" or 145" lengths, and 6, 9, 12 or 18" receptacle side. Don't know much about them, but they seem to know what they're talking about.
1971 Copper 280SL Automatic