Plumbing Questions? Ask a Plumbing Expert.
I have done some looking around as well and cannot find it AT ALL. Of course as I am sure you know Kohler says it is a discontinued item. What I suggest is calling Kohler customer service line directly. THEY may be able to get you a new cover that will fit the old one or possibly tell you where to go to get what you need. 1-***-***-****.
If I have provided any new and helpful info for you great please ask any further questions regarding and rate me once you are satisfied. If I have NOT provided any new information I am sorry I can not provide anything further per your inquiry. Please do not rate me negatively as a result. I will simply unlock the question and you can wait for another expert to try and help you. However I think Kohler company is gonna be your best shot as resolving the issues if that is even possible. There are websites/companies that have "old parts" but my resources came up blank.