Levi's Jeans labels can help identify the general date the jeans were made. The spelling of the Levi's logo will date the jeans either before or after 1971.To asses more specific dates, you will need to review the zippers, rivets, pockets, belt loops, label, and stitching. Levi's Jeans designs were originally sold to tradesmen (lumberjacks, ranchers, rail workers) and the military during World War II. As the Levi's brand expanded, their jeans became available to the general consumer market and small modifications to the designs help date them.
Look at the way "Levi's" is lettered on the label. If the labels spells "LEVI'S" in all capital letters, they were made prior to 1971. Jeans collectors call them "The Big E." If the logo appears on both sides of the label, they are likely from the 1950s. If the label is spelt "LeVI'S" with the 'e' in lower case, the jeans were made after 1971. Levi's without red labels were made prior to 1936.
Review the stitching on the inside of the button at the waistband. Vintage 501 Levi's Jeans will have a "V-stitch" characterised by gold stitching starting at the edge of the button and moving diagonally to the end of the waistband. It will intersect with a horizontal gold stitching to form a "V" design.
Inspect the quality, details, and location of the patch. All Levi's Jeans are characterised by their brown leathery label on the upper right side above the rear pockets. The patch should have the design number (ie., 501) in the lower left corner, and the Levi's 2 Horse logo stamped in red. In the late 1950s, Levi's changed the patch from a leather material to a thick card-stock imitation leather.
Turn the cuff of the jeans over. Note a vertical strip of denim intersecting along the hem. If the denim has a small white trim on either side (called a "selvedge") exposed, they are vintage. If the selvedge is not exposed, the jeans are contemporary.
Look at the waistband. Prior to 1940, Levi's Jeans had a buckle and strap cinch over the centre of the rear waistband.
Inspect the belt loops. Belt loops were added to Levi's Jeans in 1922. Prior to 1922, jeans had suspender buttons on the waistband. When belt loops were first introduced, the suspender buttons stayed with the design until 1937.
Check the rivets on the back pockets. Levi's had expose rivets from the 1870s to 1937. In 1937 the rivets were covered by the rear pockets until 1966. After 1967, the rivets were replaced by bar tacking.
Check if the fly is zipper or buttoned. Zipper flies were introduced in 1954.
Vintage Levi's jeans are highly valuable, and many fake versions have been made to mislead buyers to pay a high price. If you think you have a vintage pair, visit a Levi's retailer for information on sending photographs to Levi's corporate Historian.