How come some schools don’t have a school speed limit sign?

So it was my understanding that schools have a speed limit sign and a school speed limit sign (example in image 1). But there’s another school nearby that doesn’t have a school speed limit sign but just has a regular speed limit sign with a slow speed limit instead (example in image 2). I’ve always figured that school two had a slow speed limit because it’s a school zone but it doesn’t even have a regular school zone sign, which is weird because that road connects directly to a public elementary school. So how come there’s no school speed limit sign? Does it not count as a school zone even though it connects to a school? Is there no law in Pennsylvania that says you need a school speed limit sign?