Good point, was there a fix specifically for this? OK I have re-tested migration with version v2.03j downloaded form your link down.
After the migration the v2.03j database tables show:
JOS_VIRTUEMART_ORDERS field ORDER_CURRENCY value NULL (and user_currency_ID null)
JOS_VIRTUEMART_ORDER_ITEMS field ORDER_ITEM_CURRENCY value 0
In my case the currency values from v1.17 were not migrated.
Do you get different test results?