I would guess that since most of the Amish/Mennonite people stem from Swiss and German heritage, and stick to "old world" customs, that being uncut is probably the norm, although, I'm sure that some of them are cut, but that it's probably few and far between.
As to baptism, it's a sacrament in some churches, an ordinance in others. In "non-conformist" churches which are churches that stem from the anabaptist belief that only people who have confessed their faith as adults should be baptised, we believe that baptism is not a sacrament, but an ordinance. So for churches of Baptist heritage, as well as Disciples of Christ, Church of Christ, Bible Churches, and other churches of the ilk, and the historical Anabapist churches--Mennonite, Amish, Brethren--baptism would not be a sacrament as it is in the mainline Protestant churches or in the Catholic or Episcopal Church.
To further explain the differences here is an explaination from Merriam-Webster and Dictionary.com:
Ordinance:
1 a : a Christian rite (as baptism or the Eucharist) that is believed to have been ordained by Christ and that is held to be a means of divine grace or to be a sign or symbol of a spiritual reality b : a religious rite or observance comparable to a Christian sacrament
An authoritative command or order.
A custom or practice established by long usage.
A Christian rite, especially the Eucharist.
A statute or regulation, especially one enacted by a city government.
Sacrament:
1 a : an authoritative decree or direction : b : a law set forth by a governmental authority; specifically : a municipal regulation
2 : something ordained or decreed by fate or a deity
3 : a prescribed usage, practice, or ceremony
An ordinance is more of a testimony of an action that God has performed in one's life. A Sacrament is a means that God conveys grace.
Ok didn't want to get off on that tangent... But there is a total difference, and being a Baptist, it's a major point of interest to me. BTW, Baptists and the Amish/Mennonites share common Anabaptist heritage--it's how we have lived out things that have greatly varied--obviously--AND, not all Baptists are Southern Baptists. Some of us are Baptists who are in the South, but we are not all of the same mindset as the Southern Baptist Convention. There has been a mass exodus from the SBC because of the extreme views that are espoused.
Just a little Baptist info...