I can confirm that buglers or hornists (in the tactical sense, rather than mere hired bandsmen) were included in the two "drummers" listed per company on Muster Rolls, at least as early as the American War of Independence. At that time, a light company tended to have one actual drummer and one bugler/hornist - for some reason, he wasn't considered an "extra" unlike the two fifers in the grenadier company. At this point, there was no standard set of bugle calls published (see the article), but anecdotal evidence seems to suggest that officers familiar with fox hunting had introduced a basic set of calls that would have been in common usage across a number of hunts. One officer of the 38th Foot was mocked, initially, by his colleagues for using whistle commands, although it seems that many of his detractors found some merit in his system once the shooting started.