(read how to identify your stamp below)
This is the 3c Washington from the years 1870-1882. Used copies are very common
If the stamp has a grill embossed on the stamp (shown below) click here.
If the stamp has no grill embossed on the stamp then examine the bottom left corner of the stamp.
On the bottom left corner a shading under the upper tail of the left ribbon identifies the later issues. An example of this shading is shown below.
If you see that shading, click here. If the stamp has a date cancel and you can determine that the date is prior to February 3rd, 1879 then click here. All unused stamps belong to the latter period of numbers 182-191.
If you do not see the shading, click here.
Lastly if you see the shading on the tail as shown below AND you also see a dash or short solid line under the T and S of CENTS, as shown below. You have the 1882 printing by the American Bank Note Company. The value of these can be found by clicking here.
Extra shading under upper tail of the left ribbon
This stamp was reprinted in 1875 and it can be viewed by clicking on the numbers 167-177. These are all accounted for, so you will not own this.