Buchanan (probably) would have lost, as would any of the Pubs who ran that year, but he would have done better than Dole by virtue of his appeal to Southerners and Appalachians. With an economic nationalist leading the Republican ticket, Perot is a non-factor in this election.
323-215
I think Perot in that case would serve as a target for some strange combination of environmentalists and Rockefeller Republicans. Weicker or Lamm in this case looks like a much more fitting third party candidate or VP pick.