Do all silver certificates have US state names?

Silver certificates weren't printed with state names on them, except of course for the states shown on the back of all $5 bills - not just silver certificates.

Without seeing the bill it's not possible to give a definitive answer but you could have a bill that was overprinted by a private company and sold as an "instant collectible". If so, unfortunately that alteration means the bill no longer has any added value to banknote collectors.