To learn more about Mennonites (their history and beliefs), visit this Canadian website, or this Wikipedia entry. Mennonites are a Protestant Christian group established in the 16th century when Christians separated from the Roman Catholic Church. Among their core theological beliefs is that salvation comes only through faith in Jesus Christ. Therefore, the answer to your question is: Yes. Mennonites, like all Christians, will be saved because they have put their faith in the true Messiah and God: Jesus Christ.
[Answered by Pastor HM]