Even if they are in fact "white van" speakers, that doesn't mean they are junk, although a lot of people assume they would be. I bought a pair very similar to those when I was a teenager (in the 70s), and at the price I paid they were darn good, even impressive, for listening to loud rock music in my bedroom and later my dorm room. It's just that the guys selling them usually represent them as being very expensive exotic speakers, which they are not, in hopes that the buyer will be induced to pay several hundred dollars and feel he has gotten a bargain. I think I paid $50 or something, and even in 1978 dollars I believe I did ok.
Since you got yours at a garage sale, maybe they are "vintage" white van speakers and reflect that fact in sturdy construction and the equally sturdy, fairly efficient paper drivers that were common at the time. You might like them, or if not you might be able to rework them into something you do like. I bet the current crossover is an exercise in thrift and simplicity. But I have a feeling info on the drivers used will be difficult or impossible to obtain.
As to the "studio monitor" moniker, I'd regard that as pure marketing. I sincerely doubt there is anything special about them that would justify the term. Again, that doesn't mean they are necessarily bad speakers.