This is an interesting subject that doesn't get much attention. As far as I can determine, there are five basic aircraft categories set up for civil production aircraft: Normal, Utility, and Acrobatic (all applicable to light aircraft under 12,500 pounds MGTOW); Commuter (MGTOW under 19,000 pounds, and Transport aircraft.
There are also seven special categories established for the issuance of "Special Airworthiness Certificates": Primary, Restricted, Limited, Provisional, Light-Sport, Experimental, and Special Flight Permits.
The best and newest resource that addresses certification issues of "warbirds" is William T. Larkins brand new book on surplus aircraft. There are appendices dedicated to the subject. Check it out at
http://www.historicaviation.com/historicaviation/product_info.po?ID=10411.