According to the database, your early one shipped in April 1966, I'd guess it at upwards of $1,500, especially if the product brochure that came with it says "Polished Stainless Steel" for "Finish" at the bottom of the first page.
Your newer one has the heat treated then flash chromed stainless steel hammer and trigger, common of later ones in that second production run. I paid $1,075 for mine in that serial range about a year ago, and I was happy to have it. For "Finish" it's product brochure should say, "Satin."