Welcome to the forum , insanecollector .
The first image you posted (fish themed stirrup vessel) is intended to represent Chimu "blackware' pottery .
This type of pottery was made without a glaze process , due to a method that used high-temp sealed/closed kilns that prevented oxygen from reacting with the clay .
Although this is an ancient method , some reproductions have been made using the same process .
If you carefully inspect your item , you may find that it has been glazed ... a strong (positive) indication that your vessel is a reproduction .
You can certainly take your item to a musuem to attempt to verify it's origin (hands-on inspection is really the best , in my opinion) .
Below is an image of a Chimu blackware stirrup vessel in the inventory of the University of Maine (at Orono) .
