When I got the nuc, two of the frames were black plastic. Everything I've added has been a foundationless frame with a starter strip built in the top, but the farm with the nucs also has a retail shop and was testing the plastic ones. The bees don't seem to mind one way or the other. It did take them longer to build the foundation from scratch than to build off the plastic foundation, but I wasn't trying to get honey this year anyway so I didn't mind.