Introduced in 1953, the "Gibson Electric Bass" was the first of its kind in the Gibson lineup. It didn't find the expected popularity and was discontinued in 1958, renamed the EB-1 shortly before its demise.
In 1969, for some crazy reason, someone at Gibson thought it would be a good idea to reintroduce the EB-1. It's hard to imagine that there would have been much demand for it, evidenced by the fact that they shipped less than 500 of them between 1969 and 1972, so it's also hard to imagine the reasoning behind it.
This particular example hails from 1969 and has been modified with a 1972 embossed cover Gibson mini-humbucker in the bridge position. Of course, the original "mudbucker" pickup completely drowns it out, but it sure does look cool! This bass shows fairly heavy wear and it's very obvious that it didn't live its life stored away in the case.
Also included in this post is a shot of the EB-1 in the 1970 Gibson Bass catalog.