Inquiring minds and all of that... That's why I first posted this, since there was nothing really on the web. I would have thought that there should be something here or on Bojidar on something like this. Something in terms of "legend (folklore) has it that Pentax had the famous red SMC lenses, that folks have been hunting for across the decades". In reading the Craigslist offer and the ebay post, it says (I am going off from memory), that these items were purchased from Pentax Germany on some trip, so the seller must surely have receipts indicating such. Some sort of provenance indicating that these are truly something out of the ordinary should certainly be expected - for the price of a 50/2.
Also, I was not aware of Pentax selling off their prototypes (and why Germany and not Japan), again I would expect that Bojidar would have some information posted. The few examples of prototype items he has on the website shows a lens serial number of 000000001. Its interesting to note that on the images provided the "special" lenses have serial numbers of 2102095 and 6090680 respectfully. One would think that lens blanks would be tested and those found with the special color rendering capability would be set aside so that a limited run of these could be made. This would possibly indicate that the lens serial numbers should be relatively close together. If these are the only two in existence, and Pentax were making a limited number of these available then the collective knowledge here and on the other boards - someone would have some knowledge somewhere about these. I didn't know that vibration was such a problem with the shutter in sport shooting?
I wonder if Pentax - either USA, Germany or Japan, would or could validate the lens and body serial numbers one way or the other. It seems simple enough. Also, there seems to be an implication of a match set of body and lens, that together constitutes something very special - I would think that maybe matching serial numbers or something - other than just seeing red. There are websites dedicated to serial numbers of various Leica and Zeiss lenses. Also, this seems like something that the old Pentax Museum would have had on display.
Anyway, I am just thinking out loud and asking some open ended questions here.....