I really doubt that... Why would they go through the cost of producing a plastic version of their product when they could simply use the actual article? I worked in a cheese shop for years, these particular wheels are VERY durable - I legitimately can't think of any benefit in using a fake cheese wheel, aside from TheTetrapod's correct comment about these wheels sweating oil (which makes most people's skin breakout into acne) which can be easily and immediately solved by using a rag.
edit: and again, having worked closely with this exact cheese many many many times, that is exactly what they look like as whole wheels. I have zero reason to believe this is plastic.
I'm Italian, those prop cheese wheels are pretty common, for store displays and such. Google "Forma parmigiano plastica" and you'll find a lot of them.