Well, yes and no
Looonnnggg ago Rola Corporation bought Celestion UK but they were kept separate from USA.
In USA a "Mother/Investment Corporation" , I think it was called something like "Mutter Corporation" at some time owned both Jensen as we know it , based in Chicago, and another speaker Factory under the Rola brand.
At some time they closed the Jensen one, Jensen brand speakers ceased to be made, at least for Guitar use, *but* all machinery, stamping dies, etc. were transferred to the existing "Rola" factory.
So from a Financial/Investment point of view Rola USA and Rola UK were related, but AFAIK products themselves (speakers) were fully independent from each other.
Now good customer Fender still needed speakers, lots of them, so he started getting the "Jensen machinery inside Rola Factory" built ones, labelled Rola of course.
So in my view, Fender Rolas are at least "half Brothers" of original jensen, maybe a slightly cheaper version of them, but not *bad* by any means.
At least they were good enough for Leo, who fitted thousands of them in Fender amps.
I have repaired many along the years, using exact same parts as for Jensen, frame is also one once used by Jensen, magnet and voice coil are same size, so .....
They *might* have slightly less efficiency and brightness because they *might* have slightly wider gaps for the Voice coil, a manufacturing trick to make assembly easier and lower reject ratio, I have never put a "Twin Reverb Rola" side by side with a C12N (when I get them they are dead
) to compare them real time, but those are certainly not *bad* speakers at all.
For an "insider look" (former employees although not at the exact time of switching factory location):
https://www.audioasylum.com/cgi/vt.mpl? ... e&m=194695