It's up to you if it's a good deal or not. You didn't say exactly what CZ .22 you have to trade. They've all but been discontinued and are highly desireable. Ruger SS's are a dime a dozen and you can buy a great condition OM 3 screw, though blue, with all the goodies for the $400 you think your CZ is worth. The NM SS SS's don't go for much more.
Good deal? For your buddy...yes. JMHO