You Do Need power plug adapter while traveling from Botswana to Guam.

Here is Why You Need An Adapter

The outlet and plug type used in Guam are A and B and in Botswana are D and G. This is how they look like.

Botswana

In Botswana, outlets of type D and G are in use.

Type D

Type G

Guam

In Guam, outlets of type A and B are in use.

Type A

Type B