It occured to me only afterward: Why bother to specify "bottled"? Draft beer to go, at least in legal forms, faded from the public eye in the decades leading up to Prohibition. It's hip again, thanks to a resurgence of craft brewing in recent years, but the typography of the sign suggests that it was designed and mounted long before any such distinction would have been needed. If you were buying liquors, of course they'd be bottled. The reason is probably buried deep within the state liquor laws; this seems to be a Massachusetts thing.
Excel Bottled Liquors (a.k.a. Excel Package Store)
613 Merrimack St. (Cabot-Suffolk Sts.), Lowell, Massachusetts