In all fairness I highly doubt any of my coworkers from Pizza Hut would remember me 45 years after I worked there.
i guess you never made employee of the month and kept the little plaque?
Maybe have family o friends who benefitted from you bringing home leftovers and mistakes?
One apartment roommate worked at McDonald's and brought home large batches of McRib meat -- they couldn't keep it over night, so it was tossed or taken home.
Another roommate was my Pizza Hut Assistant Manager. His girl friend who pretty much lived with us was a waitress there.
One year, i had my store manager donate a dozen pizzas to the ECU ROTC Annual Blood Drive on campus. I was told I brought in more donations of food and drinks for the blood donors ever, PLUS it was the first time anyone brought pizza to feed all the volunteers and ROTC cadets working the event.
The next year, a tornado swept through a community near the college. i again got my store to donate a dozen pizzas to feed the volunteers helping collect household and clothing donations for the victims.
I guarantee I would be able to find a half dozen people who remember me working at Pizza Hut in the early 80s. if not, I have my tax returns and W-2s. i scan all my tax records for digital archiving.
If you can't find any evidence or witnesses to verify you worked there, you aren't trying hard enough.