As I remember, there was a core of mahogany or maple which formed the chambered body, with carved maple top and back. It wasn't just a center block. It was wider and forms the rim but much thicker than you get with semi like the 535. It would be more like the chambered LP above.
There was the 158, 155 and DC versions, plus the LE series. 155s have an access panel to the pots. The 158 doens't. The 155 is the most common.