Switching engineering specializations

[Frolsa48]

I want to make all the gnomish and goblin engineering items... Do you really have to unlearn engineering to switch the specializations in Tanaris by using the Soothsaying for Dummies book?

Edit: I see now that there's no point in switching specializations because the really high-end items require a specialization to use while the vanilla ones don't... So just gonna find someone with Gnomish specialization to make the items.