"It's yours," he said. "It cost me $13, enjoy it."
I hung it on the wall below my Marine NCO sword and a reproduction Calvary Sabre and enjoyed it. A couple years later, I posted a pic on a sword collectors website just to find out a little history, since I couldn't find it searching on the web. Boy did I get a huge shock!

My $13 Bayonet from a yardsale?
This rare Federal accoutrement is an original Spencer saber (aka sword) bayonet for the Spencer Navy Rifle in excellent original condition. Produced by the Collins & Company of Collinsville, Connecticut under navy contract, this rare specimen is one of just 750 saber bayonets made. It is just over 20¾” long, ¾” wide, 1 1/16” wide at hilt and weighs 25 ounces. Cast brass handle is 5” long and bears serial number #461 on the top flat of handle. Obverse ricasso shows the date stamped “1861” while the reverse ricasso has “Collins & Co / Hartford, Conn.” Iron release push pin intact. All brass has a mellow bronze patina overall. Blade has a single unstopped fuller, no narrow fuller and is 20 1/8” long. Seven hundred and three Spencer Navy rifles were delivered in fulfillment of the first naval contract. Each box of ten rifles contained ten bayonets. All of the Spencer saber bayonets were made in 1862 but they were stamped with the contract year of “1861”. Blade has normal light oxidation overall with no pitting. No edge nicks. Original saber bayonets for the rare Spencer Navy Rifles are very much sought after and most difficult to find in the collecting community today. This remarkable specimen, in fine condition, would make an outstanding addition to any US military edged weapon display or accouterment collection. –
See more at: http://www.horsesoldier.com/products/ed ... WPBva.dpuf
My Bayonet has Serial Number 99,
The one above sold for $1,150 and was serial numbered 401