I think Mike and sorry if i am wrong that you are saying you may be able to tell the difference by the date width.
If so then maybe a look in Gouby will help you.
He has F96 as 12-5 teeth and F97 variety BP1879Bd also as 12-5 teeth.
The F97 the most common one has widths of 11,11-5 ,12, 12-5 teeth............So Yes F96 the type can be determined by the width of the date as is only 12-5 teeth.
Atleast it is one indicator.
The only other is F98 your new one 9 teeth π
Edited ..........Sorry reading again you mean the 9 being closer to the 7...May well be π