Copyright issues with vintage patterns?

Has anyone ever attempted to sell clothes made from a vintage pattern? Do you happen to know what kind of copyright issues are involved?

The pattern in question is from 1969 and truly consists of just three rectangles. When buying the fabric for a sample (with the pattern in hand) three of the women working at Jo-Ann remembered wearing this particular style of garment "back in the day" so it was definitely popular at the time.

What are your thoughts? Thanks.