Nope, all it will do is correct the Home amount in AR and send the mathematical adjustment to Unrealized Exchange Gain/Loss account. Most likely the sales account will be missing the Home current amount for this invoice.

For OE you could trying doing a credit note and re-invoice to see what happens. You would want the credit note to also have a 0 exchange rate (to match the invoice) and the new invoice to have a proper exchange rate. If this works then do the same thing on the live data. If it doesn't work then your client will either have to live with it or have a database repair (DBR) done. With a DBR you will also need to fix the GL entry with a manual GL adjustment entry.