John W., yes, during the brief era of the germanium transistor, the RF approach was the only known way to build solid-state condenser microphones with acceptable dynamic range, so Schoeps developed and manufactured RF condenser microphones. This began with the CMT 20 series in 1963 and continued with the CMT 200 and the CMT 100 series which were produced until about 1967. Depending on the series, parallel or phantom powering was used. Each series included omni, cardioid, speech cardioid, hypercardioid, two-pattern and three-pattern models.
Schoeps was an even smaller company then than it is today, and these models weren't produced in large quantities. They were distributed and sold mainly by Telefunken. By 1964-65, low-noise FETs were readily available in production quantities. Schoeps changed over to that circuit technology, which both they and their customers seem to have preferred rather strongly. Early RF condensers (from any manufacturer) weren't as reliable in the field as the ones produced decades later; I do credit Sennheiser with bringing that technology a long way forward.
I was still a teenager then, and just starting to pay attention to recording. The people I learned from were naturally still using tube equipment, and mostly they used dynamic microphones, because condensers were expensive, fragile, and difficult to use outside the confines of a studio. From my (American) standpoint it seemed that some Sennheiser dynamic microphones were considered to have practical value (especially in broadcasting) for their particular sound quality, and by the early 1970s there was one Sennheiser omni--again, a dynamic--that was sometimes used for music. But it was a bit of an alien brand, while AKG and Beyer were the mainstream high-quality dynamic microphones for music.
Similarly the success of Sennheiser's early condenser microphones (the shotguns) was built mainly on their functionality, with sound quality taking a second position to put it quite kindly. Of course the company has enormous resources at its disposal, and eventually, major improvements were made.
--best regards