Bought a used Warmoth neck - how do I tell if Graphite or Steel?

[Rusty The Scoob]

I got a great deal on a Warmoth Pbass on TB, but without much info.  How can I tell if the neck has graphite or steel stiffener bars? 

A refridgerator magnet feels like it might be slightly attracted, but doesn't quite stick.  But that could also be the truss rod.

 

[drewfx]

I believe the "G" stamped on the heel shown here is only on graphite equipped necks: