I do not have access to real-time or historical pricing information, including the cost of a McDonald's Filet-O-Fish in 1972.
To find this information, you might try:
- McDonald's archives for historical menu pricing
- Inflation calculators to estimate past prices
- Historical food price databases
- Old newspaper articles from 1972 mentioning menu prices
- Vintage McDonald's menus from that period
Good luck with your search!