The MacBook Pro does come charged at the time of delivery so that you can check if its functioning properly and the other basic aspects but it is always advisable to charge the device before using it.

Do Macbooks come pre charged?

Its not mandatory at all to charge your Macbook pro (but you can do that) for the very first time while turning it on. The newest Lithium- ion batteries are pre charged to about 50% of the total charge out of the box.

Should I charge my MacBook when I first get it?

Apple recommends that you fully charge it the first time you use it, not before you use it. They recommend that because Macs are typically shipped without a full charge on the battery. Even if you don't, nothing bad will happen. Run on battery whenever you need to and plug it in whenever you can.