Found this seller on eBay.es selling 3D printed bits.
Check their other items - I think there's someone else doing the Sebring caps, but now you've a choice if interested.
https://www.ebay.co.uk/itm/hella-Indicator-Cover-Golf-1-Golf-2-Jetta-1-Polo-Mk1/233757287347 (https://www.ebay.co.uk/itm/hella-Indicator-Cover-Golf-1-Golf-2-Jetta-1-Polo-Mk1/233757287347)