First let me say there is no such thing as a upside down letter error.

The inscrpitions on the edge of the 2007 washington Dollars such as mint mark, date, In GOD we trust and E. PLURIBUS. UNUM are put on the edge randomly. This means one coin might need to be face up to read inscriptions while another coin may need to be face down to read the same inscription on the edge of the coin. both are accepted and not considered errors.

I've seen people pay big money for these coins in the belief they are error coins. Please do not fall for the hype.

Smooth edge errors are a whole different deal. If you can Buy one now they will only get more exspensive if they are deemed rare.

If this guide helped you then please help me by letting me know. Many read but few let me know if it helps.

Thanks and happy hunting!