Yep, I was referring to the FZ-357A which is definately high density, as is the FB-357A (I'm watching one right now read a high density disk :-)).
As I recall, the FZ-357A came (only?) in the slim variety, and I suspect the FB-357A was full height only, as is the double density FB-354.
There may have been full height FZ-357A drives at one point? Thought I had one among my spare parts, but can't find it.
I guess there must be a big list explaining all these confusing model numbers somewhere. Does anyone know of one??