I have a Lawrence flap holster. It is stamped 14S. Under that is the Lawrence logo. Under that is the number 5 & below that is 63/4. I think the 63/4 must be the barrel length.
Group 5 holsters fit the following High Standard models:
GB
GD
GE
Sport King
Field King
Olympic
Supermatic
You are correct, 6 3/4 is the barrel length.
Regards,
turnerriver