I'd guess 61-65 with that chainguard, though the fact that it has a single top tube would make me lean toward the latter end. Yet, it has an actual metal badge with rivets, which were replaced by decals around the mid-late 60s. Gambles bikes are stamped differently than any other Murray built bikes, so they're tougher to pin down. There's an old thread on the Cabe site that goes into some detail about Gambles as well as others, but the dates they came up with are mostly several years off. -Adam