What did this sticker originally have on it?

From the factory in the car no sticker

I don't think that's stock.

Looks like a part number sticker on a replacement panel. Here’s an example with a different part number.
Click to view attachment

That makes sense. I was looking through my old receipts and I see a trip I took to Automobile Atlanta in '85, and replacing the battery tray was listed as one of the items.

Can we see pics of the installation ?

I have a rain tray with that sticker still on it. could have fallen from above.

I can't get a good shot of it with the engine still in there, it's just a regular battery tray support piece though.

I was trying to get a look around after opening up my car for the first time in decades.

This is the most clear shot of the area, the hoses on the left are the AC lines coming in to the engine bay.

That parts sticker style phased in during the early 1980s, so your tray was replaced back then. I have NOS replacements with the same sticker style on them.

The production date and P/N were on it originally but likely can't be ready anymore.