Hardware

Apple reserves the right to make in-process changes to the Hardware at any time. A higher number only indicates that an in-process change has been incorporated in your sample of the product. That is a good thing, not an issue.

You likely have the orinal version, which is technically referred to as revision 1.

Potentially because during the manufacturing process timeline, Apple can make revisions to the products they sell. As you can imagine, a particular model may be sold over a course of a year or two. Within that time period, Apple may decide to incorporate revisions. This is not unusual with any manufacturer.

No, I wouldn't be concerned about it at all.