I don't know what you mean by needle bar connection link, it needs a bit more description, or perhaps picture. Any missing part can be found on thins model. I have never seen the decals with "rebuilt" in the name, but there have been a few posts on refurbished old machines. I think Miriam has a thread dedicated to them.
Yours is a model 66, maybe an old treadle converted to motor and portable case at some piont. Sometimes a refurbished machine had the original spoked hand wheel repaced with a smaller solid cast version. Other things that could be replaced was bobbin winder, numbered tension dial, often a refinish and new decals. Yours seem to have the original upper tension unit, which is fine. Refurbishing machines seems to have been relatively common from maybe as early as 1930s and well into the 1950s.