the writing on back is consistant with 1820s forward(my best guess)I found this explanation for you of what the backmarks mean...
Quality marks were the manufacturer's way of promoting their product. Typical quality marks include "Extra Rich," "Rich Gold Color" (or "Colour"), "Treble Gilt," "Best Orange Gilt," or any combination of those words ("Extra Orange Gilt," for example). While quality marks seldom tell us much, makers' marks can sometimes help to date a site.