Schrick cams are tuned S50 cams, which work with the m50, m52, s50, and s52. So, the S50 WILL work in an M52, or even an S52. Now, the M52 and S52 cams will NOT work in an M50 or S50, because they have a counter balance on them which prevents them from going in.
As for your intake manifold setup, you need to reuse the M52 throttle body, because of OBDII and the different setup provided with it. The TB should bolt up exactly like before. The only reason of going with an M50/OBDI manifold is if you did an OBDI conversion, which isn't recommended unless you drop an engine into an early OBDI car, or for racing purposes.