You have the 24c Winfield Scott from the years 1870-1873. It is uncommon. The stamp was issued with a grill (as shown below) embossed on the stamp, because stamps with this grill are so rare I have not referred to it.

It is 99.99% likely that you have the version without the grill. To find the value of the stamp click here.

Example of a grill

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.