Merle in Pa. 25 yrs. old or older get Antique Plates.
Either 15 or 20 can get Classic Plates.
With either you have to re title as Antique or Classic.
I am not sure what the restrictions are on Classic but on Antique they are stated as Limited daily use, no night time driving unless you are on the way to or from a car show. I believe both tags are Permement with a one time fee to the state. I titled my truck when they raised the registration cost doubled for trucks. I used to get antique state inspection stickers from a friebd that owns a repair garage but when Pa, went to once a year insp. they did away with Antique insp. Now all Antiques are self insp. and probably better inspected by the owner than most State Insp. Stations in Pa.
PS all insoection stations in Pa. are Privately owned but Licensed by the State and mechanics have to be licensed by the state.