First off I want to emphasize that you're right on all the really important points. The nit I will pick is that "need" is kind of a strong word, given that there's a pretty simple way to convert MM-DD-YYYY to YYYY-MM-DD format, even if it's not widely capable like a Date::* module:
# assumes you have 0-padded dates, but if you don't you can change
# the \d\d's to \d\d?'s , and do an appropriate sprintf.
my @ymd = map { my ($m, $d, $y) = $_ =~ /(\d\d)-(\d\d)-(\d{4})/; "$y-
+$m-$d"; } @dmy;
HTH
If not P, what? Q maybe?
"Sidney Morgenbesser"