Interesting non-response! FWIW, I have never had a YEC advocate (even one who claimed to be intelligent) answer that question -- and I've asked it numerous times...
AFAIK, other than the Milky Way only a couple of galaxies are visible to the naked eye in each hemisphere. Even so, I'm not sure whether a person three to four thousand years ago would know what he is seeing.
The "observer problem" is usually ignored in the many "age of the universe" debates around here. So again, I'll bring relativity and the inflationary theory to the table by mentioning that the universe is some 15 billion years old from our present space/time coordinates and approximately a week old from the inception space/time coordinates. For more: Gerald Schroeder: Age of the Universe.
Sorry, hadn't seen this Post until now.
I assume that Moses could see roughly as many galaxies as we can see today. The night sky -- like the already-mature animals, already-mature trees, and (for that matter) already-mature humans, whom God created in the Garden of Eden -- was created in a state of full maturation.
An alternative, or supplemental, explanation for the presence of distant starlight in a "young" universe is the fact that the Bible specifically says that God "stretched out the heavens" in the process of creation. Ergo, even assuming no variation in the speed of light from the first days of creation until today, there may well have been significant spatial-time dilation over the first six days of creation from a smaller "cosmic egg" -- in which light from NOW-distant stars didn't have to travel 15-Billion Light Years to reach us (assuming that our measurements are roughly correct), because they weren't as far away during the first six days of creation. (The Bible indicates that that whole universe was smaller).