Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
Yep, XD. Magnezone has Base 60 Spe, while Magneton has Base 70. I lose a bit of bulk and SpA though.(bulk might matter, but SpA doesn't Magton-120, Magzone-130)