Yes, there has been a change. The low single-digit hammers (3%, 4% etc....) are no longer glowing (which makes sense), the 30% hammers are blue and there are now 50% hammers which are yellow.
It is possible that the changes have affected the regular hammers - are they single use? I'm not testing this, I'm not crafting anything until I get an answer - I don't want to lose one of the really valuable hammers!