But if it wasn't used by one of these Olympic shooters, how much value should it have?
Well, pretty clearly, it has a value of $4725. The market has spoken and left little doubt. That it is worth a lot less to most of us, tells us only about the individuals reading the thread, not the market.
Years ago, things like Unertl scopes were pretty cheap around here. The market was relatively low for them. But ebay came along and the prices really jumps as the coasties drove the prices up. We midwesterners said no way they are worth that much but the market proved otherwise.
There may not be too many people willing to hold up a market that high for this particular type of rifle, but there aren't many of those rifles either. I suspect you could wait a lifetime and never see another. So, it is what it is.