Hi Glenn, your button will probably date between 1810 and 1820, based on the size and the backmark that you have on yours. The flat button era was over by the late 1830s as the two-piece buttons came into vogue. In fact, Robinson's went into receivership because they were late in producing a cloth-covered two-piecer that, by 1840, had replaced the typical flat button.
The very fact that you have a "quality" backmark tells us quite a bit. Prior to 1796, as found in Bill McGuinn and Bruce Bazelon's book, there were very, very few backmarks stamped onto a button. Why? The shank installation technology just wasn't up to snuff.
If you have a customer whose wrath in growing each time he looks down to find an empty button hole do you think he'll buy a product again if he can identify the maker? In other words, he's missing four out of five buttons. He checks the survivor and it has a backmark of "Bill's Buttons." He will be certain to steer clear of that maker unless it's one last visit with a ballbat..
But in 1796, the British government in an effort to stem some of the poor quality, mandated that button makers had to inform the prospective customer of the ....here's the key ..."quality".... of the button: Treble Gilt, Best Colour, Double Plated, etc. In your case, a ********** quality button.
Notice we don't have bms that say "Super Duper Shank" or "No Yanka Shanka" (<~~ that was a Chinese firm, I believe,
).
But at least the British government was trying to address the problem of poorly made buttons.
As time when on, when shanks got to the point they couldn't be pulled off between a team of oxen and an elephant, you began to see the actual maker's name. Or at least a retailer's name. Why? The quality was high enough to where the product would bring favorable public opinion to the maker.
Anyway, I say all that to point out that even a "Best Orange Colour" tells you a lot (along with OD size) as to when the piece was actually made.
You can pretty readily identify country of origin by the craftsmanship, too. If you have a fairly crude piece, you may be looking at "local" manufacture, ie Richmond, Fredericksburg. (Not to be confused with Confederate "local," but same idea) Whereas the British product is years ahead of anything domestic until you get into the 1830s when the race was about even heading into the two-piece era.
All of this information can be found in Bruce and Bill's outstanding button backmark book. This isn't an advertisement for them, but a recommendation. Armed with that book, you can tell the dates of most 1800s military buttons, and a lot of civilian items as well.
Sorry it's a bit long. But hopefully this helps.
Richard