It was a toilet seat custom manufactured to fit on a P3 Orion toilet. It was custom built to original specs to fit on an aircraft that has been out of production for years. It bolts directly in place with no airframe modifications or recertifications required. Recall that aircraft parts have an expensive certification and maintenance tracking protocol. Custom builds to spec and short runs make for expensive items.
That’s what I remember also. Some of the high-priced items, like the famous $500 coffee pot, were specifically ordered to survive a B1 bomber crash landing. Also, since the fleet was only going to number in the dozens, I didn’t have a problem with it.