Looks like a toy to me. From the first photo, I’d guess it is only eight to ten inches long, compared to the grains of sand it is laying on.
Did some more research...
There are several websites selling the plans to 3-D print small replicas of the GBU-53/B that look to be the 8-10 inches in length (not the 8 inches in DIAMETER of the real thing).
I think the Yemenis are trying to fool us that they have the real thing.
Agreed! Looks fake based on the size of the sand grains.