The question I'm asked most about bats is, "How can you tell a 'real' bat from a store bat?" What I hope to do in this section is explain the traits of professional model bats and provide information that can help date those bats to particular eras. There are few concrete rules when it comes to authenticating and dating bats, but there are many well-researched guidelines that can help.
I plan to include information from as many bat makers as possible and will add bat makers as I'm able. For now, though, I'll focus on the most common trademarks, Hillerich & Bradsby (Louisville Slugger) and Rawlings (Adirondack). Much of the information on these manufacturers was drawn from two books, Bats, Professional Hillerich & Bradsby and Adirondack, 1950-1994 by Malta, Fox, Riddel and Specht; and MastroNet Reference and Price Guide for Collecting Game-Used Bats by Bushing and Knoll.