Hi Tenngun,
Since the P1718, or Pattern of 10,000 British Long Land "Brown Bess" Muskets, the front sight was the Bayonet Lug. That continued throughout all future British Flintlock Muskets of the 18th through early 19th centuries.
All "Regular" British Regiments had been rearmed with P1730 Muskets between 1730 and 1739, though that was the Garrison or "Peace Time" Army strength and did not include the additional muskets needed when the British Army increased in size for War. British Regiments often doubled in strength during War Time.
So when the War of Jenkin's Ear broke out between Britain and Spain in 1739, there was the usual "Urgent" need to provide muskets to arm the increased number of British Soldiers in War Time. However, the winter of 1739-1740 was so bitterly and unusually cold, all the rivers and streams in England that powered the forging trip hammers and grinders were frozen over and barrel and lock production for Musket/Military Arms came to a stand still. What had been an "Urgent" need for additional Military Arms became an "Emergency" in England.
Between 1740 and 1742, England was compelled to buy 15,000 "Dutch" Muskets and 36,000 Dutch Barrels just to arm British Regulars for the War of Jenkin's Ear that morphed into the War of the Austrian Succession of 1744-1748. By the time things improved in England where British Ordnance began making P1742 Long Land Pattern Muskets, all of those Arms had to be reserved for British Regulars fighting on the Continent and in Scotland against the Jacobite Uprising of the "Bonnie Prince Charlie" that ended at Culloden in 1746. So NONE of the then "New" British Ordnance Pattern 1742 Muskets made it to the American Colonies during what was called "King George's War" here in the Colonies between 1744 and 1748.
https://en.wikipedia.org/wiki/King_George's_War
The Land Forces of the British attack on the French Fortress Louisbourg in 1745 were virtually all British Americans from New England and Nova Scotia. Some British War Ships also supported the attack and taking of the Fortress.
https://en.wikipedia.org/wiki/Siege_of_Louisbourg_(1745)
What has been very difficult to almost impossible to find is documentation on the French Small Arms that were captured at Fortress Louisbourg in 1745. There were about 1,400 French Troops who would have been armed with Military Arms and another 900 Militia whose Arms seem to have been unknown. What we don't seem to know is how many Military Arms were in storage there.
When Fort Louisbourg was given back to the French after King George's War, the French restocked it with Military Arms in a large measure. When it was captured again by British and British American Forces, it held 15,000 Military Arms of all sorts. However, that is probably a much larger number of Arms than had been stocked there prior to 1745. Had there been that large of numbers of Arms captured in 1745, Massachusetts probably would not have gone to the expense of having Orr make 500 more muskets.
Gus