E. Michigan Ave., Flagpole hole (?)

What’s this metal disc in front of the Stadium District building, on the south side of East Michigan Avenue between Cedar and Larch? Could it be one of the holes drilled so businesses could display flags, as mentioned in a 1949 [Lansing] State Journal?

I find it doubtful, since this entire block was redeveloped in the 2000s, but since there are no dates on any of the sidewalks here, it’s impossible to say for sure how old they are. It does look like there is a hole here and that the metal plate is designed to be removable for some purpose (otherwise they would have just slapped some filler over the hole). There are a row of them up and down the block. They are too awkwardly placed to imagine them being used for flagpoles again, if that’s what they were originally for; this one, for instance, is in front of a window.