No, I don't think there really is a reliable data base on prices....for those days gone by ..../ unless you could find some old catalogs in an archive somewhere.
In the 3rd edition of the S&W standard catalog/collectors book ...there is a note that a model 686-3 in 1989 was mfg'd in a 6", finished in midnight black stainless, .375" semi-target hammer, .312 smooth combat trigger, red ramp, white outline rear sight..and there were reportedly 2,876 made and retail was $445.
( now, I have never seen one ....and I'd sure like one ...and would pay handsomely for it today ...??) ....but ..
You'd have to assume - if yours is a more common stainless version - it was less ...but $50 ...maybe $100 less....I don't remember !!