I put together a fretless from a Hohner neck I got here and an anonymous P-type body from eBay (possibly a Kay, as it has a six-bolt neck fixture).
Because of the six neck screws, I had to plug and redrill the neck.
When I put it together, I was able to pick it up by the headstock, with the bass hanging vertically, before I put the screws in.
I'll never sell it. Great bass? No (but perfectly adequate given what I paid for the parts). Mine? Damn right.