666 is not embedded in a barcode — The short answer is “no”
The longer answer follows: Some people have taken the following passage from Revelation 13 to support their claims that the barcode had 666 embedded into it.
Revelation(17) so that they could not buy or sell unless they had the mark, which is the name of the beast or the number of its name. (18) This calls for wisdom. Let the person who has insight calculate the number of the beast, for it is the number of a man. That number is 666.
Barcodes are all database driven. The barcode only represents a series of numbers containing a prefix, item numbers and a check digit. We’ll discuss the intricacies of barcodes in subsequent chapters.
The numbers corresponding to the barcode are scanned or entered into a database exactly as indicated below the barcode (the human readable numbers). Along with the barcode number, the information relating to the product including ‘regular’ and ‘sale’ price is also entered. When an item is scanned, the information is pulled from the database and the customer is charged the proper amount of money, at the same time, inventory is adjusted downward.
There are the three sets of guard bars, two bars on the far left, the far right and in the middle. Since these guard bars appear three times in a barcode, and look similar to the number 6, some people have claimed that the pattern 6-6-6 was embedded in every barcode.
According to Mr. Laurer, the inventor of the UPC/EAN barcode, “There is nothing sinister about this nor does it have anything to do with the Bible’s mark of the beast. Each character is a fixed length, 7 modules and composed of two spaces and two bars. From the outer ends toward the center, the character starts with a space and therefore a single bar is required to ‘close’ the character. The other bar is used to allow the level setting (gain) circuitry to adjust to the contrast of the particular symbol. The center pattern is narrow space, narrow bar, narrow space, narrow bar. This pattern is 4 modules wide and distinguishes it from the a 7 module character thus giving direction and end information to the logic. The assignment of digits to specific patterns was arbitrary.’
Sources: http://www.laurerupc.com/ and common sense.