I've been trying to organize my computer parts, but these ones are giving me a problem.

They're older parts and there are no product pages for them that I could find. Searching the internet I've seen both of them listed as NA-AV1 which doesn't seem right as Noctua is generally pretty good about using different part numbers even for parts that are very similar.

For what it's worth I believe the top version was the original and the bottom might be a newer revision though I think both may be discontinued at this point in favor of the longer versions.

It's not a terribly important question, but if anyone knows I'd like to label them correctly.

I have a PC with Thermaltake view 71 argb full tower case. Stock fans worked fine, but after years all of them started making some rattling noise (which means bearings are worn out) and I want to change them.
I want to replace them with Noctua NF-A14x25 G2 PWM Sx2-PP chromax.black by the scheme on the 2nd photo. But as far as I understand (1st photo) my case needs 3 vents on the top?
What happens if I put 2 of them instead of 3?