Identification of old guitars is somewhat of an art, requiring knowledge, research, and resources. Since there is no formal standardization of identifying characteristics, manufacturers were free to choose ID methods. With the price of vintage instruments on the rise, and the proliferation of counterfeit and modified instruments, it is important to use all available resources, several identification methods, and a dose of common sense.
Serial numbers may seem to be the most reliable method of identification, but not all manufacturers used them, and they are not always reliable. Serial numbers can be obliterated or changed, or may have disappeared entirely.
On some guitars, the serial numbers are difficult to find. Older Fender guitars, for example, stamped the serial numbers on the heel of the neck, requiring removal to view the numbers. Other manufacturers printed serial numbers on tags inserted into the sound or f-hole of acoustic and hollow-body electric guitars, which may have been removed, become unglued, or have been lost altogether. There are also instruments that have no markings at all, or may be missing information due to refinishing, theft removal, or damage.
Design and Features
Guitar shape, finish, logo marking and designs can be used for identification purposes. Some manufacturers changed headstocks and body styles, or offered special paint finishes during certain model years. Logo designs and other graphic markings are also used to identify guitars, which older manufacturers tended to update with the times, or to mark the beginning of an era or company buyout. With popular vintage reissues and outright counterfeits, it is sometimes hard to distinguish old from new, making identification difficult.
Hardware and Electronics
Electronics and hardware can be used as substantiating evidence to back up other ID methods. Tuning keys, bridges, tailpieces, electric guitar pickups, knob style, and internal wiring can help in verifying a guitar's age. Bear in mind that when older guitars were new, owners did not always consider them future collectibles. In an effort to update their guitar, owners may have changed one or more parts to improve the instrument's performance.
Books and Websites
Books and websites exist to help identify older instruments. While websites are convenient, they may not have accurate information in their database, and should be used as just another authentication method.
Professional dealers and appraisers use personal knowledge and guitar "blue books" to help identify and place value in an instrument. These same books are available for purchase at many music dealers.
Tips for Purchasing
Buy from a Reputable Dealer: Ask for documentation and substantiated proof of the instrument's authenticity, and perform your own research using the given information. With an established dealer, you may have some recourse if the guitar is not as claimed.
Avoid Buying Sight-Unseen: Buying guitars from private parties through auction sites or out-of-state advertisements is always a gamble. You are not only taking a chance of purchasing a guitar that is not authentic, but the true condition of the instrument will not be known until it arrives.
Be Wary of Private Sales: Always ask for any documentation and evidence, and do your own identification before you buy. Of course, there are many honest private sellers, but there is no guarantee that they themselves may have unknowingly made a bad purchase .
Use Several Identification Methods: Serial numbers and other obvious ID methods may not be enough. If an instrument has a serial number dating it to 1950 for instance, also consider that the body, headstock, hardware, electronics, and overall condition is consistent with the date and age.
Get it Appraised: Professional appraisers are knowledgeable and experienced, and will provide a written appraisal for documentation. If you think you may sell the instrument in the future, an appraisal certificate from a qualified, established appraiser will help you in the sale by removing many of the questions for the new buyer.