The email information posted above is (kind of) a reiteration of what i posted over in your other thread regarding your piece:
http://www.treasurenet.com/forums/showpost.php?p=4746192
Attaching any kind of -specific- date to your plate is impossible without proofs/cartouches/inspector/arsenal/organizational markings - your going to get a range at best, which has been determined... And it is simply not reasonable to believe that one can determine what 'model' your plate came off of by the plate alone. I accounted for the range of musket pattern possibilities over on the other post i did (imbedded link above).
Furthermore, for those who may be unaware - a 'fusil' is nothing more than what would later be known as a carbine.
Someone above mentioned the words 'carbine-type'. Yes sir (as you seem to be aware) that in regards to the British Empire, a fusil was simply an adaptation of the standard issue longarm via a reduction of the OAL of the barrel for improvements in maneuverability. The 'Brown Bess' was THE standard issue longarm of this time, and the specifically-dated examples mentioned in the previous postings are just two of these adaptations.
'Brown Bess' pattern variations and their issuance was dictated by the utilizing party - 'Fusils' were namely found amongst dragoons, fusiliers/artillery escorts, and marine/naval boarding parties at this time. These fusils were/are better known as 'Short' or 'Light' Land Pattern Muskets... Again, just one of the many patterns of the Brown Bess.
If you like comparisons, think of the Single Action Army colt revolvers... existing in 'patterns' such as the Artillery, Cavalry, Gunfighter, Storekeeper and Target models... At the end of the day, they are all still a Colt SAA.
No disrespect intended here, but the gentleman who offered the information via email didn't seem too confident in his abilities... He was on the right track, but quite frankly his specific naming of any connection to a 'fusil' was a reach for sure.
Without playing the diversionary 'state your credentials' game, i will again say with confidence that based upon the screw count & pattern, the specific contour and shouldering of the tang, and the pronounced heel - your plate is from one of the Brown Bess patterns and that given your location you may most certainly attach a American Revolution provenance and not be labeled a 'dreamer' or 'wishful thinker'.
And once again, beautiful find!
~Tejaas~