I think it was a third party lens made in LTM for one of the Japanese Leica clones. Canon, Nicca, Honor etc. They also made a 28mm lens in LTM mount. I still kick myself for not buying it when I saw it 20 years ago. And to think, my justification at the time was, " Where will I find an affordable 28mm finder?"
Komura makes good third party lenses as well as very good enlarging lenses.
-Paul