Most likely they will bring you over to western arch, so you would need a 110, 119,129 setup. Your in one of those areas that has either arch. If you have any non mpeg 4 equipment, then you would indeed need a Western arch setup.
The installer will have both antennas available. If EA or WA works on your existing mount, that is what you will get. If not, you will probably be given a choice.
I am setup to have my dish repointed on Saturday. My locals come out of Saginaw. Hopefully the installer shows up with both dishes and we can figure out which on will be the best.