While the advice above is generally good, to the best of my knowledge, there was never transferrable FUSC in 2018. If it existed, it would probably only be for very early adopters who have some deal where they get it on all X and S purchases for life, and for that reason, you'd probably be hard-pressed to find one that didn't specifically advertise it. That having been said, assuming one does specifically advertise it, you should use that advice to verify, because odds are the advertiser is mistaken.