I inherited my dad's Browning shotgun back in 1983. It's a Belgiam made 5-shot humpback, gold trigger, engraved "Sweet Sixteen", ser. no X917--. Dad bought it from his brother around 1960-ish for just a few Michigan pheasant hunting outings. The gun looks very good and shoots smoothly.
I've shot it occassionally over the years at clays and fairly recently at a local three-gun match friendly to 5-shot capacity shotguns. It shoots fast and easy.
I've been trying to find the manufacture date with only a little luck. (Browning site and Shotgun World forum) It was narrowed down to 1953-1964. A guy on another forum said he found "1953" for that serial number. I've asked the poster for a link to the source but haven't heard from him yet.
I'm hoping to find a verifiable source for the "born on" date. A copy of the original manual for the Sweet 16 would be a big bonus.