Obvious answer was get both,
Wondering if the 686-4 is a 6 or 7 shot and is it a SB or RB frame ?

IMO a 7 shot 686 gets a premium over a 70's era N prefix 28-2 but not all 28's are created equal in value.

A 28-2 with the S serial prefix and diamond Magnas or targets gets a premium over later N serial prefix guns with non diamond stocks.
A 28-1 or earlier 4 or 5 screw gun gets the bigger premium over all the above .