Is it possible just to make a rule of anywhere you see a date format of MM.DD.YY rename to YYYY-MM-DD? if there are 6 separate date instances... do the first one where the first one is, second one where second one is...
e.g.
rename file
01.01.01 - 02.01.02 Receipts dated 01.03.01, 01.15.01, 01.28.01.pdf
to
2001-01-01 - 2002-02.01 Receipts dated 2001-01-03, 2001-01-15, 2001-01-28.pdf