From Update on the Transition from Republic Wireless to Boost Infinite but also pertinent here:
Will former Republic members with locked phones be subject to Boost Infinite’s unlocking policy, which, as I understand it, is the phone must be on Boost Infinite’s network for one year?
Members will have access to Boost Infinite phones post migration to Boost Infinite. If a phone is purchased at Boost Infinite, the Boost Infinite policy will apply. If a phone was purchased at Republic prior to migration, the Republic policy will apply.
If it were me, I would still make every effort to get my phone unlocked prior to migration. There’s no reason to wait and you’ll save yourself potential hassle convincing Boost Infinite support you bought your phone from Republic Wireless later.