It's not just the AC casings. Like I said, if you're looking at a place, look at the serial number and the year is encoded in it. Also, it would actually be illegal for them to replace the interior units without significant renovations because the units aren't up to modern code - the intake vent is too small and the bedrooms don't have a return vent (opening the door doesn't count).

The location on that corner with the extra buses does definitely add to their appeal. I would put the dog park and spruced up (tiny) pool in the category of cheap lipstick for exterior appeal. It's a good business move for Gainesville when most people are going to stay for a year or two and it's good enough for them, but if this was a non-college town where they'd be after tenants to stay for 3-5 years, they'd have to gut renovate that place to maintain top of the market rents.