I registered the '73 last year (regular registration) in March or April... TWICE, plus additional fees because PennDOT screwed up... Oh don't worry, they've got fine-print that covers their butts, they're not responsible for any errors or mistakes.
Here it is, a year later, I still don't have that registration I paid for. So when my temporary registration expired (it's supposed to be there for you until your registration card & plate sticker arrive), I had no choice but to park my '73 even though the weather was still very nice and perfect to be driving around in a 340 Duster.