I had one that I bought new in 79 (Koa Mockingbird bass) and it was one of the best playing and sounding basses I ever owned.
You can hear it on this youtube site after scrolling through Tad's talking at the beginning. I used it when recording the bass on the song Molokai Slide in the 80's. This song was a #1 hit in Hawaii and is now a part of the folklore of the island. The bass sounded superb in the studio.
https://www.youtube.com/watch?v=2XUPVtOhtPY However, I never used the built in preamp, as it didn't do anything but make the bass louder (no tone change). The build quality and fit and finish were fantastic and the balance was perfect on these. You would not be unhappy in buying one. The Eagle was the exact same bass with a different body style and sells for less. It just had different ?wings? on the same body. I like the Koa wood ones the best and they are worth more.
Beware any that are advertised as vintage that do not have the full electronics package. They made many, but they are not the same sounding instrument. There was also a well known store owner who bought many left over bodies from BC Rich, especially in the Wave style, and finished them and people sell them as original a lot. Neil Mosier is the man for BC Rich info.
http://nealmoser.com/ They were made from 76-77 to date, but you want a vintage one with a 'USA' build, though I think they were made in Mexico.
Many songs, like 'Good times' by Chic and songs by Seawind and several other groups in the 70's, were recorded with them. Trust me, I never heard of anyone laughing at these hand made basses before. Rick Derringer played the guitar version of the Mockingbird. They are highly respected and for good reason. Mine was $1,100 new in 1979.