I noticed in hgn_mothership.ship that the “Production 3” hardpoint allows you to build “Hgn_MS_Production_Frigate” and “Hgn_MS_Production_FrigateAdvanced”. Has this always been the case? Are there really two separate subystems that go by these names?
Yes, there really are, and has been since non-remastered. There is no functional difference between them.
There’s also carrier versions.