I am getting ready to migrate to a Sprint 700P from a Zire 72. Is there anything that I should know about to help the migration go easily?

Also, I have a couple of other questions:

1) I got the phone off of eBay. How will I know if the phone has had the "MR" (What does that mean anyway?) to 1.10?

2) Since I will have nothing on the Treo, is it necessary to back it up before I do anything?