In states that don't have their head up a certain bodily orifice "pre-smog" is a rolling window. Requiring people to maintain emissions systems in their stock configuration on cars pushing 50 is insane. If you really are hell bent on making people smog stuff that's old and uncommon to the point of being a rounding error to the big picture then just stick a sniffer in the tail pipe and pass it as long as it meets or exceeds the standards it was built for.