You Do Need power plug adapter while traveling from Mauritius 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 Mauritius are C and G. This is how they look like.

Mauritius

In Mauritius, outlets of type C and G are in use.

Type C

Type G

Guyana

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

Type A

Type B

Type D

Type G