Sam, I understand exactly the point Mr. Armstrong was making. Of course people are free to make whatever alterations they want to their firearms. And others are free to disagree. But, that was not my intention, nor the focus of this thread -- which is what these alterations do to a Parker Repro in terms of value and collectibility.

Greg,
Recognizing that your question is of two (2) quite different parts, I will address each as I see it.
1. Collectibility: I consider very few Repros as "Collectibles". They have not yet reached that status. Maybe in 50 years. So if not collectible then they are just shooters and speculative investments.
2. Value: Even as mere shooters modifications reduce market value. The gun I posted a picture of with the recoil pad, when this post started, was purchased by me for $2500 with case, cover and original SBP and screws. That was, at the time, about $1500 below market for an unaltered 99% gun.
Bob Jurewicz

Recoil pads & choke alterations reduce value/collectibility.
Expertly enhanced engraving, muellered borders, case coloring & stock finish are positives to me, but probably have little effect on value/collectiblity.
Emphasize expertly, otherwise a mediocre job definitely reduces value/collectibility/desirability.
If in the future repros achieve similar status as original Parkers, any alteration will be seen as a negative.

I agree with Sam and take comfort in knowing that Doug Turnbull's grandson will be able to fix ANYTHING 50 years from now!

If you don't plan to sell the gun and are pleased with the re-case colors then by God, just enjoy the gun and let your heirs worry (or not) about re-sale value. Beauty is in the eye of the beholder and you're the beholder and that's all that matters. my 2 cents only.

Using Bob J's terminology, "speculative investments" as opposed to real collector guns, be aware that the modified Repro market will not include those buyers interested in "speculative investments". The modified Repro market will also not include collectors. What is left is the shooter market where buyers are interested in Repros at well below retail prices. I would love to buy another 28 gauge in "shooter" condition, at about $1500 to $2000 below normal retail price.