1921 Morgan Mint Error?

Can you get a closer image of the section in question. From this image it does look like it was struck through, but seeing it closer would help.

From what I see I think it is a legitimate strike through error. What made it happen was something was between the planchet an the die when the coin was struck. Since the die was harder the object was pressed into to the coin. Then after the coin came out of the press whatever it was fell off the coin leaving the depression behind. Since the 1921 is a very common coin I would think it would add some value to an error collector. Not a lot of value because as an error strike throughs are relatively common. Fortunately this is a relatively large strike through which increases interest. To a dollar collector it would reduce the value.

Since the coin is circulated, without the error it might be worth around $20. With the strike through My guess would be $27 to $30 but I'm no expert on errors.