No idea. I bought the car exactly 2 years ago this month, from a salvage yard in SoCal. It’s funny, I cleaned and inspected the cowl on the passenger side because I was going to place the ECU for my FI on that kick panel, and wanted to make sure it wasn’t going to rain on it. My friend has one of those scopes to look in, and amazingly, no rust at all.
But for some reason, I didn’t look on the drivers side. So, since I decided to rebuild the door hinges, I removed both fenders. The drivers side was packed with dirt, so I decided to now clean that side of the cowl, and through that drain hole on the side, I see this round end, looked like a big nut of some kind. Wouldn’t fit through the hole, so I pushed it away from there, and in the light, a screwdriver.
And, no rust!