Yours may not have had it. I don't know the ins and outs of which ones got them but I am fairly certain not all did receive them. My friends '75 had no air pump. It had a lot of work done to it before we came into possession of it though. I do know the two I owned in the 80's were unmolested when I got my hands on them back then. Both were Ohio cars. One ended up a loud and obnoxious '78 and one a first date safe stock '76. I know the one came from a DSO in Michigan. They were not California cars. Both had less then 75,ooo miles when I got them. Both had failed pumps. The '76 I never touched the engine. It's AIR pump was bypassed already. The '78 I rebuilt the drivetrain so it all came off and I had to get the plugs for the heads and a shorter fan belt.
It was a matter of an hour and removing a few bolts to get pump off, a bolt or two for the AIR lines and two bolts holding the lines to the back of the head. Once removed you installed threaded plugs that were about $5.00 into the heads and bought a fan belt for the cars without the pump. Some just smashed the AIR lines to stop them leaking but the plugs were readily available and cheap.
Is your state really that strict on this old of a car? I was an AIMS tester here in Ohio back in the '80's. I thought most states have exceptions for cars this old. We haven't had emissions test here in Ohio for 20 years now so I am out of the loop. When we did have them anything older then 25 y/o were exempt.
Can you register it as a collector or historic vehicle and avoid the inspection? Only pursue these if your are not planning a daily driver. Here in Ohio I technically cannot drive it to the store or just to visit a friend using historical tags. Only to a mechanic or a parade/show and less then 2,500 miles a year. I will have regular plates for this car which is a travesty in my opinion.