The JCI 48/91/H6 case design with the single, centered, oval-shaped vent port goes back a long way. I've used them in Diehard, Interstate, and Bosch (before it switched to Exide) form with no issues dating back to the late 80s. It has the siamesed vent caps that need to be pried out. There are even little slots to accommodate a flathead screwdriver.
A few years ago, they replaced it the one with the small center handle, and dual side vent ports, which looks
like this.
The Walmart, NAPA, O'Reilly, Autozone, AAP and other chain store JCIs use this case design. I haven't owned one, but don't really see a way to check the water level unless one pries off the large strip to reveal the cell ports, which may or may not be doable without damage.
But there's an alternate double-handle case design like the Costco Interstate #29, with individual caps.
I've seen this one with Costco Interstate, Interstate, Diehard, Delco, and Champion labels, often without handles which I guess reduces the cost.
In actuality, I think only the case tops have changed; the body casings all look to be the same.
I have one of the Costco #29 currently. Once the warranty expires, I'll have to see if it's possible to check water level without damage.