Model Number. This is the model or lot number of the pair of jeans which is used to identify them. On many Levi 's jeans the model number is printed on the back badge or tag situated above the back right pocket on the waistband.. - The History of the Vintage Levi 's 501 Jean patch still intact, you 'll be able to identify it from examples on the internet of almost every patch that . - If you get lucky and spot our famous red tab as you scan the racks at your favorite thrift shop, here a few ways to help determine when they were . ///ehowbeauty Identifying vintages Levis is som She 's wrong because .