70 B-body Non-AC boxes had both the 2936681 and 2936680 inked part numbers. I had stamps made for both. The difference being an early/late year thing or St. Louis car or Lynch Road car thing. If everyone would chime in we could likely figure it out.
2936681 number on my 12/69 built Lynch rd car.
As I recall a late build St. Louis car I had had the 2936680 box I'm going to venture to say it is a late/early build thing. Cars built prior to Jan 1st had a #681 and cars after had a #680.
