If your pump is warn... then yes. In the Merc SportJet... it's an aluminum housing, and it's about $500 to replace. Impros can put the stainless insert in for less than an OEM replacement.
On a regular seadoo... I always say no. The Rotax powered boats and ski's have a plastic ring, and it's only around $40. It's easy to replace at home, and it protects the impeller.