front? rear? what?
many front will have steel pistons because most buyers buy the hype and myth that "plastic" pistons = junk.
rebuilt rears often have rebuilt pistons and does minimum work have problems right out of the box or a few months after.
Others rebuilder/remanufacturers are more thorough and make a good product.
Store etc won't know and likely won't care to find your answer.
You have to find the actual rebuilder and ask them.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)