More precisely put... I have seen a premium on the K20/4, K35/2, and some on the K50/1.4. I haven't seen any on the K135/3.5, K200/4, but a bit on the K105/2.8. (Of course, the K85/1.8 is prohibitively expensive.)
The K120 and K150 don't come up often and I suspect there isn't a premium on them vs the M120/2.8 and M150/3.5 versions. Regards, Bob S.
