I personally think the 639’s are really cool pistols. They are a great candidate for a rehab project and are worth the time/money put into them. Unlike blued examples they are easier to make “new” again.
I’ve posted about mine before so this is just a reminder. I got it in a box, as in it was a box of parts. Many parts were missing and it looked like it had been dragged down a gravel road. Like new original ambi grips and right side safety/de-cock lever and screw were the hardest parts to find. I put in a 3rd Gen ambi but have since got a lever and screw. (I’m leaving the 3rd Gen one in.) I also got a few excellent original magazines just because.
I probably made it too shiny but at least it looks better than it did when I got it.
Jim