Date of manufacturer

I have an American Eagle 7.65 Luger with a serial number of 18255. All parts appear to match with 55 or 255 numbers stamped on them. I do not see the date of manufactur on the pistol but I have not looked at it in depth as yet. It is in good condition with 90% original blue. The eagle is worn a little but the rest of the markings are good. I would like to put it up for sale but would like to know the year it was made. Everything appears to be original.