I don't think we have many Aspen 1920 owners on here, and certainly not many if any recent posts. Since I have the newer Aspen C3 and not the 1920 I am doing some logicking here and will do my best to explain my reasoning:
1. If those holes were intended as air intakes, what would be the point of the bolt on outside air kit adapter that goes at the bottom rear of those stoves? You would be bypassing that and drawing interior house air, defeating the purpose of the OAK. This stove is approved for mobile home installation which requires an OAK.
2. The side plate/baffle pieces shown in the parts diagram only make sense to direct air up from underneath the stove to the top burn tubes (lining up with point #1). As you noted the manual states that the secondary air intakes ultimately deliver air to the 3 stainless steel multi-ported tubes at the top of the firebox. Those two holes you have taken pictures of appear to be straight in... If they were intakes for the secondary tubes, you wouldn't be able to see straight through into the fire.
3. I have a very hard time believing VC would've designed holes that appear to be straight into the firebox like that. The fact that we can see orange fiery goodness inside means that sparks, small embers, etc. could jump out through those holes. That doesn't make sense to me on any UL-listed stove that has been designed in recent history.
4. I did a lot of research on the Aspen, including the older 1920 model, when I was shopping around and ultimately settled on buying my C3. I never saw any photos, videos, etc. referring to intake holes there, nor could you see into the firebox like that in any of those photos/videos.
From what I can tell on the parts diagram, I am thinking the two fixed secondary air intakes are at the rear of the stove, on either side of the primary air damper. You might be able to see these by removing the rear heat shield? The air then goes through the bottom to the front of the stove, up the sides around those baffles, and to the secondary burn tubes. Finding those two holes would prove without a doubt where the intended secondary air intake holes are.
I want you to like your Aspen and use it safely. I love my C3 so far. It looks like the forum consensus is that what you have with those open holes at the corners is not safe and at best will result in short burn times or at worst cause an overfire because there is just no control of the air there.