History
Some of the most widely known and valuable old posable dolls are original Barbie dolls, first made in 1959. Not all old posable dolls are Barbie dolls. After Mattel designed the Barbie doll, other posable dolls started to be designed and gained popularity also.
Identification
The swimsuit Barbie can be identified per the The Doll Company website (see References) as having holes in its feet so as to be able to pose on a wire metal display stand, which was included with the doll. Original Barbie dolls also had wire metal earrings in their ears. Among the most common issues encountered with old posable dolls is that their skin has become discolored from the plastic absorbing discoloration from the metal earrings or the stands that come into contact with the dolls' skin.
Solution
There are some do-it-yourself remedies to stop the spread of green on the dolls' skin. However, depending on how old and how valuable the doll is, it is wise to first consult professional doll restorers. There are a wide variety of doll restoration professionals who specialize in restoration of specific types of old posable dolls, including the Barbie doll.