[1960 Buick Electra 225 accessories codes on body number plate]

Could anyone help with deciphering the accessories codes on the 1960 Buick Electra 225 body number plates?  I've searched this forum and the internet but can find nothing addressing the accessories codes.  I found lots of info on the trim and other codes on the plate, but nothing on the accessories codes.  My plate says "ACC  N7-U7".  Thanks in advance for your help.

[1960 Chrysler New Yorker fuel tank]

Thanks for the suggestion.  I called and they do not have one.

[1960 Chrysler New Yorker fuel tank]

Can anyone suggest where I can find a fuel tank for a 1960 Chrysler New Yorker 2 door hardtop coupe?

[1960 Buick Electra accelerator ball stud]

Thanks.  I saw this on ebay last week and called the guy, but he said it would not fit my '60 Electra.  And, even though the ad says it will fit 1960-70 GM cars including Buicks, when you look at the compatibility chart below for the different models and years or when you plug in 1960 Buick Electra it says that the part is not compatible.  

[1960 Buick Electra accelerator ball stud]

I cannot find an accelerator gas pedal ball stud for my 1960 Buick Electra to fasten the base of it to the floor.  Is there a workable substitute...maybe from a different year?  Would appreciate any advice or perhaps a link to previous threads on this topic.