Dull earl heat shields are cadmiun silver plated steel, a process not commonly available anymore due to being extremely toxic. Dull chrome, which is regular chrome w/o the polishing final step, a near exact duplicate. Or do-it-yourself the frugal way:
scuff VERY thoroughly w/ scotchbrite and lighter fluid a common shiny chrome shield, then brush on dull aluminun paint. If you can draw a straight line, you won't have to re-do the black areas. Looks like the real deal, although the dull aluminun paint tends to rub off a bit if you handle the parts. Shiny shields look so gaudy in comparison. How do owners of later CB750's live with things like shiny heat shields, quiet pipes, tanks w/o wrinkles, long chainguards, finned oil filter covers, rolled front fenders, 48 T sprockets, pipes w/ lettering, etc, is beyond me.
Repops available from Japan, we are in process of ordering goodies from there and we can get a CLUB DISCOUNT on unstamped pipes, gauge covers, dull heat shields, etc if we order together. Anybody want in on this? Keep posted and be an active part of this club and bulletin board.