The label SMR applies to a wide range of reactors.

The BWRX-300 is at the upper end of that range and I don't think claims of factory-production of the whole unit were ever made for this reactor.

That said, even the much larger AP-1000 had fairly large modules made in a factory. In fact as far as I understand that was one of the problems with the Vogtle builds, because doing that only really makes sense for a larger number of units, not for just two unites.