This thread shows the most information I’ve found regarding stock 66 steel wheels. I would imagine you might have convinced a dealer to give a $5.00 discount for keeping the new truck hubcaps, but don’t think you’ll find anything in writing confirming this as an option.
http://67-72chevytrucks.com/vboard/showthread.php?t=381738&highlight=stock+color+wheelsThis Ebay listing claims to offer 66 Chevy wheel covers, but I have no idea if these are stock or not:
http://cgi.ebay.com/ebaymotors/Hubc...99QQptZMotorcyclesQ5fPartsQ5fAccessoriesI wouldn’t think these would be necessary for registration, just something that looks somewhat original. I wouldn’t imagine the DMV employees are experts in antique trucks.