The side-heatsinks is the later model. Basically the side-heatsinked versions are the same as the *01 versions (201, et al) in the older case. a good bargain, and a nice amp overall. I have a CA200 and it has served well. Has a propensity to pop its fuses on big input transients (e.g. make sure you turn it on last and off first) from other gear switching sometimes, and if the speaker wires cross or even look like they will, it will tend to blow a fuse on that too. Which is a PITA since you have to pull the top cover to replace them, plus they take an odd shape/size, ... but other than that, great amp.
-Ed
-Ed