Possible to use unlocked TMO GS8 on Sprint?

Will Sprint let you use a Galaxy S8 that was purchased on T-Mobile, but then was paid off, unlocked and flashed to sprint firmware on their network?

The GS8 phones in the US are exactly the same hardware on each carrier, they just run different firmware (that can be flashed - so that's not a problem either). The main issue I'm hearing is that Sprint may refuse to add phones with IMEI numbers from other carriers. Does anyone know if this is true or not?