If your OT agreement were to convert to or become a follow-on effort as a procurement contract, all of the normal procurement rules would kick back in for your new procurement contract.  It would require a new competition (unless DoD were to use 10 U.S.C. 2371b(f) for a follow-on production effort) or a justification for sole source.  You would treat it as a new action in the traditional procurement process.  Having begun the process as an OT would give little to no advantage to you.