I would consider those as variations of a "U-frame" open baffle. The holey back panels didn't have a lot of acoustic effect apart from minor reflections back to the driver, but the depth and shape of the space into which the rear wave exited would have had an effect on the sound, as it does in an H or U frame. There would be minor cavity resonance and standing waves between surfaces. Because this is not a tuned box, either reflex or sealed, I would consider these 'fairly' open baffles, or at least near the open baffle camp.
After all, these terms can be somewhat nebulous and not completely defined—like whether passive radiator designs are properly considered 'ported' as many would have it.
Another old and largely forgotten configuration could be (but wasn't) called a variation on the resistive port, and that was an open backed box with multiple layers of absorption completely filling the interior. The rear wave would be attenuated and delayed, but not reflected back, so I guess the radiation pattern could have been cardioid down to fairly low frequencies, like the Geithain studio monitor designs of Germany.
