The spotting just could be due to the firing process. You can fire certain type of clay in a wood kiln vs a elec kiln. The ash gets on the pieces and can spot it like that. (My GF is a potter)
It is beatiful. To my eye, it is probably the same maker (or factory) as the piece on ebay, but is more sophisticated, with the more tapered design and the white instead of green pattern. So, I'd say built later.
The ebay piece was hand-made in the southwest and is listed as vintage but not antique, so somewhere between 20-100 years old.
if you look closely, VERY closely at the details of yours and compare it to the eBay one above, I think you will find that they match up exactly (look at the chip for instance on the top spine of the iguana). This would indicate that it is not hand made in the sense that it was a pinch pot or thrown but instead is a cast piece.
If you research the eBay piece you will find that it has been for sale for a while on different sites for different prices....I found 150, 165 and 200$...with VERY little description...which is suspicious and suggests to me that the seller knows EXACTLY what it is but is trying to get top dollar without lying outright.
I think your pot is from Mexico and no older than the 1950's but more likely the 70's. It was probably originally sold in a local U.S. "Mexican arts store", bought in a small batch from the actual Mexican family maker.
i thought the same thing at first, but I suspect if you could take shots at the same angles as the eBay piece you would see that they are the same. I believe the perspective is playing tricks.
If you look very close I think theirs was electric kiln fired and mine is wood fired. As a person posted the sparks from wood can hit the piece causing the deposite look.