I have a G17 Gen 1 import with s/n: CDxxx US. I bought it used around 1987, but never sent it in to Glock for the upgrade. Should I? I know that Gen 1's are getting harder to find, and while I know that the pistol won't ever be really valuable as a collectible, it may be a little more valuable as time goes on. Will doing the upgrade harm the future value of the gun? Or is it something that really should be done, regardless?