I don't know what the exact value of the older Boston Whalers, but the ones I have seen, THT, several neighbors, and foes I have know, Had to resore the older boats--not cheap. The foam can become water logged that this is a major issue.
My impression is that the C Dory holds it value better. Part is the design, part is the construction, and part is that there have been very few changes thru the years. For example a 21 foot Boston Whaler of the 2006 Vintage retail with trailer and motor runs about $23K. The purchase price was about 50K. Compare the the 2006 C Dory22, selling at about 40,000 and a new price of about 50K.
Go back to 1993, the C Dory cost about $25K and today will sell for about 25 to 30 K This is what they cost in 1993! Boston Whaler 1993 22 footer, cost about $30K now selling high blue for $9400. Most likely the C Dory will also be in better shape!