YES, but it would take hours . . . basically CBO tries to take into account the actual size etc of your tables & indexes to minimise execution time ("cost"), RBO does it by "rules of thumb". CBO is generally recommended.
Chapter 4 of the 8i designing & tuning manual has more info.
"The power of instruction is seldom of much efficacy except in those happy dispositions where it is almost superfluous" - Gibbon, quoted by R.P.Feynman