Engine assembly: "sealing compound"

[tgraham]

I'm reading through the directions on assembling the engine. Page C:07:07, which outlines fitting the upper and lower crankcase together, instructs the assembler to "smear the assembly face with sealing compound." What exactly is "sealing compound?" I would guess that, since it appears that it needs "sealing compound" all around the metal casing joints, Hylomar (or probably better: anaerobic sealant) would be the choice, but I've been known to guess incorrectly...

Thanks!
Travis