I am also of the opinion that they should be left as is... To each his own is a valid statement, which I agree with, but here is my opinion. If it was a generic bullseye type built by one of hundreds (thousands?) of guys that made them over the years, perhaps I might be tempted, but if they are signed or at least known to be from a well-known, now departed artisan I would keep them whole. If they no longer work for you, then sell 'em, no dishonor in that, but as Gary said the cost of good base guns is so cheap that even if you took a "loss" on the bullseye guns, I think you would still break even or come out ahead.
For example In a local shop I recently saw four bullseye guns, two were Clarks (one a longslide). Three of the four have sold over the last 5 mos, yeah thats slow but this is a small shop. All were priced between $1000 and $1250. If you only got $900, then a add $450 for a basic Springer and you would have a nice pistol. While Dave said that he did a "conversion" for something like $300, I would also be tempted, but I think that most gunsmith would want to change many more parts and not see the inherent quality in those pieces and the price would go up. Not too many smiths want to redo someone elses work, for fear of increased hassle and cost, and rightly so.
OK rant mode off.
Dave you are an Iconoclast and every board needs an intelligent one to keep us honest!

So keep writing.