Maximum price that silver reached in 1980 was just under $50 an oz, and it didn't reach that again until just briefly a few years ago. And then it crashed again. And if someone REALLY wanted one of those seats the molds and casting resin is still available. You could probably make your first one for around $50 (less the coins) and subsequent ones for less because the mold is reusable.
What would make my day would be either NGC or PCGS encapsulating the toilet seat in one of their slabs. Would it get a details grade for harsh cleaning or get a clean grade?