I can't say as I know, but when I recently broke down and bought the lyman luber-sizer, I bought a few different kinds of lube to try out. SPG is one I ordered, and I hadn't opened the box til I read this thread.
Taking the stick out of the plastic, I gave it a good sniff, and ya know, it smells very much like my Beeswax/crisco lube, which, (say it ain't so), smells like beeswax. Looks and feels like it too. Well, we all know it CAN"T BE THAT SIMPLE, but if there is tallow in it, maybe there's some beeswax also. Maybe it's got some soap or some sch, I dunno. I ain't a lube guru.