Slide value?

I recently purchased a Ronin EMP/4", and I already have a scratch (down to metal), on the top of the slide. I've touched it up with some cold blue (worked pretty well), but I am not satisfied with such a fragile finish. So, I'm going to send the slide to Evolution Armory and have them do it in DLC.
I have no idea what a new slide would cost, and short of contacting SA, does anyone have a suggestion of how much I should insure it for?
I will (finally!) get to my range this afternoon and function test it before sending the slide off.
I take very good care of my firearms, and this scratch surprised me. I believe that I did it with my wedding band, while racking the slide. The hot salt bath bluing is pretty, but it is not remotely durable.