Granite Mortar & Pestle Question

Hello, I currently own a 2 cup granite mortar and pestle. The inside of the mortar is unpolished, as is the tip of the pestle, and a couple inches up the sides of the pestle. This seems to be ideal for my usage. I've been making lots of curry paste, but found out quickly I need a larger mortar. I ordered a Cilio Goliath. It is a granite mortar and pestle. I believe it's about a 4 cup capacity. The inside of the mortar is unpolished, as I expected. However, the pestle is fully polished down it's sides. Only the pounding surface of the pestle is unpolished. Because the sides of the pestle are completely smooth, it feels like it wouldn't be very effective at grinding. I haven't tried using it as I'm leaning towards returning it. Should I return it and order a proper thai mortar and pestle? I don't understand why they would have fully polished the pestle. Thoughts? Thanks! submitted by /u/Audi403