I don't know. Same exact item, made from plastic, aluminum, and magnesium, I think plastic is still the lighter weight of them all.
Of course, durability is a whole nother issue.
http://www.arboristsite.com/community/threads/mastermind-meets-the-ms241c-m.253473/
Give it a little scroll. One of Randy's had damage to the clutch cover during shipping. That definitely does not bode well for use...