The opening voiceover states that the date is "February 28, 1980-something," yet the episode revolves around Barry joining his high school's football team. High-school football is a fall sport. There is nowhere that the season extends into late February.
The football field pictured has a FieldTurf surface, yet this kind of artificial turf wasn't introduced until the 1990s. Astroturf, the artificial surface available in the 1980s, looked completely different, and only professional sports teams used it on their fields. Artificial turf on high-school fields didn't become prevalent until the 2000s.