The 380 was a low level one. I've got a 500 that I'm refinishing and restoring and it sounds and plays great. Not that sought after but I've seen the top of the line ones go for ~$500. Great great pickups.
Tons of info here, though a little incomplete, at least with regards to transitional models (mine is from 1969 or 1980 and is a SL500S with a maple neck and agathis body):