Amber Snuff Bottles with dots

[OldBot]

My husband is a surveyor and has found a LOT of bottle treasures in SE Texas. He has many of these amber snuff bottles and we have learned that the dots on the bottom designate the strength. We are wondering why there are different configurations on these four 4 dots...is there a way to date these? Sharing only one he has with a scrap of a label...Levi Garrett & Sons? He has never found a 1 dot bottle...is it rare? Thanks for any information.