You could certainly contact Bernhard Vollmer at Schoeps and give him your MK 6 serial numbers. Studer, especially in the United States, had some Schoeps stock for a long time, so almost anything is possible. (I bought capsules from them, too, by the way.) The simplest way to put the question is: Did the 10 kHz response in the cardioid setting have a ~2 dB elevation? But depending on what was done when your capsules were last serviced (e.g. if new diaphragms had to be put in), their response may have changed.
I think it's fair to say that Bernhard doesn't prefer to think in terms of "old vs. new versions" of a capsule, when the nominal curve of its 0° frequency response still falls within the tolerance field as that model of capsule had been specified previously. (See the attached curve from a few years after this change occurred; an older capsule that was perfectly flat at 10 kHz would still fit it.) So I wouldn't suggest asking him about this in terms of "versions." But he's certainly aware that there have been adjustments throughout the decades, and he knows very well what they mean to the sound. He's not only in charge of all repairs, but also of quality control.
P.S.: For older MK 6 capsules that haven't had their gaskets (seals) updated, it's preferable to store them in the figure-8 setting; this can help to prolong their ability to work in all three patterns. But if yours have been serviced at the factory at all recently, it's probably not important.
P.P.S.: There haven't been any knockoffs of Schoeps capsules to my knowledge--certainly not the three-pattern capsule, which is a bear to assemble. Knockoffs of the Schoeps M 221 B tube amplifiers (bodies) were made in Hungary about 40 years ago, many of which are still seen on eBay and in the for-sale lists of less-well-informed "vintage" equipment dealers. They were made rather haphazardly with lower-quality parts (especially the tubes and transformers, which are critical), and they tend to have levels of distortion and noise that Schoeps would never have allowed. Schoeps doesn't accept them for repair since they aren't Schoeps products.