Some popular Myths & Misconceptions...

the twelve apostles - an often quoted statement referring to the number of bottles in a set. - does not appear to be a contemporary quote, but possibly 19th century.
pale blue bottles - a popular re-enactor based misconception, not sure when this started, but has seemed the universal colour NMA bottles get painted. The colour under the obvious years of grime is actually a darker green / grey shade of blue.
using a powder flask with a set of bandoliers - another re-enactor 20th century-ism. Some illustrations of musketeers show a small 'touch box' or flask being used instead of the usual priming bottle. I would suggest that these are based on the 'gentleman' soldiers, or civil guards, as this would add quite a lot of expense to the sets provided in their hundreds to the armies. Some fine examples of these flasks survive, but it is doubtful that many of them were designed for the musketeers. Calivermen, and cavalry would have found these items useful. The norm for a musketeer seems to have been a bottle with a spout.
Carrying an extra powder flask is a 20th century convenience for re-enactment purposes., when extra powder is required for demonstrations. 17th century soldiers were issued a set number of charges, the expectation presumably that the action would not last more than twelve shots or that the soldiers were to refill their bottles from the budge or gunpowder barrels. 'some musketeers of ours running hastily to a budge-barrel to fill their bandoleers, and being careless of their matches, the budge barrel took fire, and blew them up' Lord Orrey's Art of War (ditto)