Came ashore on Omaha beach

This just went on consignment at my local gun shop. I stopped by on the way to the local gun show this morning. It went ashore with the owners father when the artillery units were able to go ashore. It came home with him after the war. Initials on holster are also on right side of frame.
https://www.milsurps.com/images/impo...show1921-1.jpg
https://www.milsurps.com/images/impo...show1871-1.jpg
https://www.milsurps.com/images/impo...show1861-1.jpg
https://www.milsurps.com/images/impo...show1881-1.jpg
https://www.milsurps.com/images/impo...nshow191-1.jpg
https://www.milsurps.com/images/impo...nshow189-1.jpg
https://www.milsurps.com/images/impo...nshow190-1.jpg
The shop is asking $1800 but I think it would be 1000-1200? If I could what should I offer?

Offer them $1500-1600, 1000 to 1200 seems a bit low for a Colt

My thoughts were the top of slide and the front strap are very thin and rust like on their finish and the initials take some value away in my opinion. I am still trying to learn percent of finish and this is a original finish. I placed it in the fair to good condition, which I'm OK with purchasing a pistol in this condition because that price range is close to do able for me.( using The Standard Catalog of Military Firearms as a guide) It is a little out dated as I've had it for a couple of years now.(2009) If I pursue purchase I'll have to dissect it to make sure all the parts are as they should be.

You are probable right on the higher estimate as I'm trying to be optimistic.