You Do Need power plug adapter while traveling from Pakistan to Guyana.

Here is Why You Need An Adapter

The outlet and plug type used in Guyana are A, B, D and G and in Pakistan are C and D. This is how they look like.

Pakistan

In Pakistan, outlets of type C and D are in use.

Type C

Type D

Guyana

In Guyana, outlets of type A, B, D and G are in use.

Type A

Type B

Type D

Type G