[QUOTE=T-Mar;21605924]The seial number, as reported, is atypical for Bianchi. There should be another number associated with the 'D'. Typically, it would precede the 'D', but Bianch QC left something to be desired, so it be after the 'D'. Offhand, i don't think it's early 1980s as most members miss the serial numbers from this period, which are located on both sides of the seat lug. Also, you mention the frame size stamps, suggesting, the numbers are on the BB shell, which would push into the late 1980s.[/QUOTE

Thanks for the feedback. One with the same frame and serial number format just showed up on eBay. I’ve been looking for 3 years and one shows up a couple days ago. Serial number under the bottom bracket is 59 (Drive side) and D.297 (opposite side). Listed as an 80s Specialissima Mondale Reparto Course. Not sure what the difference is between the D.297 and mine that is D.266. I have seen other 80s Specialissima Bianchis with the same serial numbers format, but with a C rather than D. So, can I assume the eBay posting is correct. I’ll post pictures as soon a I have enough posts.