I think it’s well known Koetsu never wound their own SUT’s, but sourced them from a Japanese maker - the question is "who"? Haven’t seen an answer on that, yet. The new metal-box SUT shows some additional components inside there too (resistors) along with damping materials - so they’re probably doing something to "optimize" sonics for Koetsu. The old wood box SUT’s are different - and they lean towards the "detailed / fast" side of the sonic spectrum, with a little extra energy in treble and without destroying the midrange romance (like Lundahls do). It is a VERY good match for Koetsu carts. Can sound great with other carts too, but you have to watch that treble getting too hot. I don’t know how the metal boxes ones sound.
For Ortofon - their Verto shows Lundhals inside. Pretty much any transformer with that distinct flat rectangular metal box is going to be a Lundahl. Lots of component manufacturers use them (line inputs too). I’d be surprised if Ortofon wound any of their modern SUT’s. I’d be surprised if ANY cartridge manufacturer did.
EAR is impressive for winding their own transformers (and their MC-3 / MC-4 SUT’s are superb), but they’re a component maker, not a cartridge maker.