I'm extremely skeptical. There is a real lack of evidence.
The distances between stars are so vast that the energy requirements for interstellar travel are by our standards almost infinite. The cost of the moon program in modern dollars was around a hundred billion dollars. Sending little robots to Mars costs several billion dollars. Any kind of interstellar program would cost at least a trillion dollars. It is not about money. It is about resources required, either by us or by another civilization, which are enormous.
There are also practical considerations. Space is very radioactive making it impractical for travel. It takes a great deal of effort to keep humans alive in space. Also, anything moving faster than 1% the speed of light is in danger of being obliterated by a grain of sand that happens to be in the way. At 10% the speed of light, the super thin interstellar gasses, although almost non-existent, are enough to create considerable resistance. I have heard that it would difficult to go any faster than this.
For this reason, if I were designing an interstellar craft, I would make it shaped like a giant needle with it being very thin. I don't know if this is practical.
