Each state I'm sure has slightly different laws and procedures regarding registration, VIN's, and pink slips (titles). Missing the VIN plate for any year is probably going to cause a problem just about everywhere. "68 really isn't any different than '67 and earlier when it comes to a missing VIN. Even the '69-up cars missing a VIN will probably have to get a new VIN assigned in some states (they do here), regardless if you have VIN on the pink slip or not. I have seen a few skate through by talking the inspector into using the fender tag, but, they're really not supposed to do that. In fact, they're supposed to certify that the VIN plate has the proper rosette rivets, which fender tags don't have. If I had a car missing the official VIN tag, I'd probably try to get one made, round up the correct rivets, and install it, as long as I know had the correct VIN.