68 Camaros are the most dificult to identify, since the cowl tag has little information, it only tells the type of engine, date built, interior and exterior color.
From the information you posted you can tell its a 2dr sport coupe with a V8 engine built at Norwood, Ohio the third week of April. It has black standar buckets and its original color is Matador Red.
If the rear end is original, a 12 bolt and 5 leafs spring would suggest at least a SS. Take a look at the CRG site, specially at www.camaros.org/diffs68.shtml
Also post your car information there.
If you have any of the original documentation, built sheet, Protect-o-plate you will find all the information required.
Hope this helps