Answer:
No.
If two rectangles are congruent, it means they are the exact same shape and size.
I have uploaded an image with this answer. In the image, you can see two rectangles with the same perimeter. However, they are not congruent because they are not of the same size (even though they are of the same shape - a rectangle).
Hence, two rectangles may not be congruent if they have the same perimeter.
