I dont know how much your dash has been hacked,but originally it would have had the usual 70's 'spindle fit' am radio. Mine has a period 'Jensen' rad/cass which may or may not have been dealer-fitted from new,but it looks period.In fact its not even connected to the aerial (buried in the centre of the windscreen).Tape player part of it gives typical 70's tinny rubbish sound for playing 'Peaceful easy feeling' whilst cruising tho! I would have thought ebay would have thrown up something appropriate & cheap...
Quite agree re the wheels. Mine wears the factory 'rally steel wheels' it was built with. I do like the Z28 '5 spoke' steels of 77 too. I spotted some steels like mine last week here
http://cgi.ebay.co.uk/4-Chevy-Chevrolet ... 500wt_1154
athough its ended,looks like they didnt sell & he may be worth a follow up.....
I think mine were silver from factory as the body colour paint is lifting in places to show proper-finish silver underneath. Body-colour wheels may have been an option (havent checked),either way it seems to have been quite common place;I like it & I believe mine has been like that for years.
If you havent been there yet,visit
http://www.nastyz28.com/camaro/camaro77.php
I spent ages on there when I first bought my 76;-tons of gen & the forum is excellent. I found my build sheet stuffed under the passengers rear seat base. With that you can refer to the web page above to easily decode it & find out more about your car. Its quite addictive!
Cheers,Andrew