The lizard definitely resemble monitor lizards or biawak. Does the level of intricacy or the style of the carvings suggest a region? Or perhaps the designs themselves? If those are indeed hornbills, the they are biawak, and the biawak are eating dogs... then maybe Borneo?
Is Borneo not known for hornbills, do Dayaks not have a lot of dog symbolism in their carvings and tattoos, and are biawak not very common there?
But does not look like a Dayak-style shield from the little I have seen in pictures... and hornbills, dogs, and monitor lizards are found in Africa as well...
Just a thought from am amateur
But then again, maybe it was made more recently, and maybe for the tourist industry