There are two issues here:
(1) Can lead leach into glass? Excellent question. I am no chemistry expert but I turned to a google search on this lead leaching into glasss search It would appear from reading a bit that using even leaded glass where liquids are stored for relatively short periods of time is safe.
This bottle has no indication of being made of leaded glass. Might it contain lead? Possibly, but unlikely. Also, your contents are not acidic or alcoholic which, from what I understand, would cause greater leaching of lead.
I personally use old bottles to store both liquids and dry items but do not use any items I suspect to be made of lead glass. Such glass is quite heavy (thick) and will have some degree of a ring to it when flicked with a fingernail.
(2) Staining. Your bottle is stained or etched which often occurs from a portion of the glass matrix leaching out - often as a result of the item being buried in the ground or full of a liquid. The only way to remove it is to polish the bottle by a tumbling process.