LBP & SBP Spindle diameter question (Drums)

OK, I may be confused, but here is what I’ve concluded:
All large bolt pattern drums are designed to fit only on 1.25” spindles.
All drums designed to fit 1.375” spindles are small bolt pattern.
Are my conclusions correct, or have I missed something?

Thanks
Scamp

If I'm wrong some year/model info would be appreciated.