Yes. Although I don't believe the secondary Progenoid is used at all in a Marine. It's only to grow a second one so the Space Marines can have a variable number of soldiers. Think about it. If there were 1000 Progenoids to begin with, then they would be whittled down slowly, and would have to rely on the Adeptus Biologis, which I'm sure would be quite interesting, especially for the Astartes.
-Dirge
-Dirge