Yes, but despite what you may have read, "I wish I were rich" is not a subjunctive clause. The subjunctive is a clause type that uses the plain form of the verb, as in "It is vital that I be kept informed". The "were" in your example is best called 'irrealis', a special mood form instanced solely by "were" with 1st or 3rd person singular subjects.

Understanding the Context

Many speakers prefer to use the preterite "was ...