Yes. I had dinner with the tech director of Electro at the NYAS last fall, wherein he assured me that the ECM 1 Mk6, although internally reconfigured, uses the same Class A analog output stage and Cirrus chipset as the original, as it's so good. So yes, an old Mk1 with the diode/cap mod back then is STILL a reference level CDP.
(The food at Hell's Kitchen was great, but of course overpriced.)