OCEAN CITY DAIRY milk bottle - Ocean City Maryland - Rare? Vintage?  Age?

Description

This listing is for the
OCEAN CITY DAIRY, Ocean City Maryland, milk bottle
shown.
It's not very often that I am stumped on an item but this is one of them.  I picked it up a local yard sale  The seller knew nothing about it other than that it was from an uncle's collection.  I also was not able to find anything on Ocean City Dairy. I checked online and with the Ocean City Historical society.  All they knew was that there were and are several dairies in O.C. over the years but they knew nothing of this bottle or dairy.  I have no idea how old this piece is.  It seems very old to me but I have no back up to guarantee it.  I'm hoping someone looking can help me identify it so I can pass the info on to others looking.
It is 9 1/2" high.  In overall very nice condition with no chips or cracks and very little wear. Nice paint.  Marked
"Ocean City Dairy, Ocean City Md., 5 Cent Store Bottle."
Marked on the bottom is "
Registered, Sealed in PA."
Also has an
"E47."
Has the break off circle on the bottom which also suggests that this is an older bottle. A very interesting piece of which I have not been able to find another like it. No idea how rare (or not) this bottle is.
Will be packed securely and shipped timely.  Thanks for looking.