I see the picture on Gunbroker - per SCSW that Product number should have "early Slide" but pictures show Novak sights which would be a later slide - mounting slots are significantly different.

1990 Literature is first to mention Novak sights and it appears you had a choice of the early fixed sights or Novaks on most pistols and also had option of adjustable but not on 6906 - just lists Fixed Sights for 6906.

May be "Special" was early implementation of Novak sights but that would be inconsistent with Prod Code for Early Slide - or maybe slide has been replaced with newer slide.

As to 2482 "Date" Code - I doubt that was conventional code - last digit of year followed by day number - obviously not 482 days. And 1992 catalog shows 108211 Product code with curved trigger guard. Also by 1992 Novak sights were standard not Special.

Seller says he has paperwork - that could explain.