Late letter of recommendation?

So I’ve got someone sending in an additional (not required) rec, but it’s going through snail mail. With the Nov. 1 deadline in 5 days, I’m concerned that the letter won’t make it in time. If its 1-2 days late, will my application be considered without it? Or is there a period of “sorting” after the deadline before applicants are evaluated? I did mention in the Common App that I had an Additional letter of recommendation coming, so would they wait for it? Thanks.