I am not entirely clear on the position of the 55 and 7 in relation to the OI mfgr. symbol. Usually they are to the immediate left and right. It also matters whether there is a dot after the right number
However, it is not possible to accurately date all OI bottles from what I understand.
As for use of the bottle - some type of liquid. Getting more specific involves scanning advertisements from the 1930s/40s/50s in hopes of seeing a bottle of this shape in an ad - or finding a picture of one with a label.