I'm sorry it took me so long to get back to you. I have been out of town and this is the firt chance I had to look for a code on the other tank. I looked and felt it over and do not see any stampings on it. If you can tell me where on the tank it may be, I can give it an even closer look. All the bubbly paint on the tank makes it hard see anything. If you do have interest, the auction for the tank ends tonight. Here is a link:
https://www.ebay.com/itm/372722277603
I'm sorry I could not be more helpful with the code. I'm still not sure what this fits. Maybe second gen F Body?
Thanks,
Jason