I do not understand your question. What do you mean when you say that two serial ports connected to 2 T1s with 2 different sets of public IP addresses. And then say one of the serials uses ip unnumbered.
However I think that the answer to your basic question is clear. Unless there is something else about your environment that you have not described, yes 2 public IP addresses can be routed over E0. (Just be sure that whatever is behind the router has routes back to the public IP addresses).
HTH
Rick
HTH
Rick