I don't think you'll get it for a grand, nor do I think the seller will get his $1800.
The trouble for the seller is you can buy brand new similar size boxes from HF that are all shiny and new with ball bearing drawers for that much money. I doubt many of these HF boxes that see pro service(as nearly all SO boxes do) will be kicking around in forty years.
Those look to be in really good shape so if the drawers work well they represent very good value somewhere in the middle. I'd be putting cash in front of the seller.