Just be aware that some people don't take kindly to their work being "ripped off" so to speak, the person who made the original seat may have spent lots of $$$ and more than 100+ hrs on the plug, the mould and then the first seat, ask them first and give them credit for the work they have done.
Infact it's common place in some industries to put a lot of effort to try and stop others copying an idea or product. (like grinding part numbers off, adding hidden security codes etc.)
I remember my grandma sometimes missed out the odd ingredient

when someone wanted a copy of
her special recipes