Based on the serial number, it might have been made in 1966, although Wing serial numbers did not follow any definite pattern. The bow was probably made before the introduction of fast flight string, so you should use B-50 or B-55 string on it. You may want to ask what string is on there now. If they say it is fast flight (anything other than B-50 or B-55), that might be a good reason not to buy the bow, as fast flight string puts undue stress on the limb tips of bows that were not designed for it. There is nothing wrong with string that isn't fast flight, it's just that fast flight is 4-5 fps faster. In fact, some people prefer to use the older strings for various reasons.
Wings were good bows. I have never owned one, but I like Bob Lee bows. The ones I own now are my favorite recurves.