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

Here is Why You Need An Adapter

The outlet and plug type used in Bolivia are A and C and in Guam are A and B. This is how they look like.

Guam

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

Type A

Type B

Bolivia

In Bolivia, outlets of type A and C are in use.

Type A

Type C