Does reordering table rows reduce the time for subsequent ordering with the ORDER BY clause? Is there any run-time advantage gained by changing the order of a table's rows to match the expected ordering of the ORDER BY that is in a slow select?

(assuming unique alphanumeric index and no auto-increments if these matter)
No it won't make a difference. You're using the same records to query and order by regardless of the order of the rows. I'm sure there's other tuning metrics that can be assessed if your query(ies) is(are) running slow.