Nice! I'm very curious how it'll work out! I hope you don't have troubles with centimeters and inches in a Stonehenge stage-prop kinda way:) In that case you'll end up with a mandobacker.
Nope, a 4005 doesn't have a centerblok. It has a kind of an H-profile, like the JCS bass. There are pics on the net of the insides of 330s and 360s and that's the same.