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The six pointed star could have been put in by a licensing agency. Prior to California going to a statewide licensing system in 1977 each city had their own symbol which they would stamp into a bicycle's frame upon licensing. The six pointed star was employed by the city of Berkeley, California.

In 1972 Berkeley's Bottecchia dealer was a shop called The Missing Link.

You will be able to get much more useful information from forum participants regarding the cycle if you are able to post some images.

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