Re-blueing on Pre-27 S&W

[K-9]

What effect on value does re-blueing have on a classic revolver? The one in question is a S&W Pre-27,3 1/2" .

Thanks for your expertise.

[4V50 Gary]

Any collectible gun should remain in its original condition. So, don't blue it unless it's rusting and bluing is the only way to save it.