I bought replacements from Scuderiaparts.com
15811787 Protective Cap
It's like a $1, but the shipping is a killer. I bought air and cabin filters and some other miscellaneous parts so it worked out for me. If you're just buying the cap, you're better off 3D printing one out of TPU material. PLA is going to be too stiff. I actually found a rubber bumper from the local hardware store that sort of fit, but opted to buy the OEM part since I was already getting some other parts.