exxongraftek

I recently purchased a bike equipped with a first-generation Shimano Dura-Ace component group. The date codes are pictured below:



The list of codes on vintage-trek.com dates these as March 1994 - far later than the 1970's when these were actually produced.
However, a bit down the page are the Suntour date codes, which would date these to March 1976.
I know there are other instances where the two makers seemed to swap their date codes, apparently by producing products under contract to their "rival."
So what do I have here? Suntour Dura-Ace? What say all of you?
I have no room left to store these parts, regardless. They are used but not abused. Any bump up in the value due to the unusual date codes?

T-Mar

What you have is pre-1976, first generation Dura-Ace. To the best of my knowledge, these codes have not been definitively decyphered. I've seen R, S and T codes. If we work backwards, that could be 1973, 1974 and 1975 respectively, with the 2nd letter being a fortnight. That should not be too far given that the first Dura-Ace product was the crankset, in 1972.

They're definitely not SunTour codes or SunTour manufactured product and the date codes do not influence the value.

exxongraftek

Thanks! I'd not heard about these date codes previously, but since the bike frame they were on dates to NLT 1972 it makes perfect sense.
And of course there would be no value bump (other than being made so early) given my poor luck... ...and I really appreciate your help.

Metacortex

I've been tracking these codes for several years now and agree with the above except that I've seen P, Q, R, S and T codes and so far have determined that they represent 1970 through 1974 respectively. For example, here is a Schwinn Approved Model J (Shimano built) freewheel dated Dec. 1970 (12-70). With the outer dust seal removed the freewheel body date can be seen as PL, which (considering that the freewheel body had to be made before the entire unit could be assembled) I believe corresponds to 1970 (P), June (K or L fortnight). If so this means that the R and S codes on the OP's parts would correspond to 1972 and '73 respectively.