Out-of-the-box "date format" values for "default" and "en_US" locales

In FreeTDS, the "default" and "en_US" locales have the following values of
"date format" defined in locales.conf:

[default]
    date format = %b %e %Y %I:%M:%S:%z%p

[en_US]
    date format = %b %e %Y %I:%M:%S:%z%p
    language = us_english
    charset = iso_1

Is there a reason that FreeTDS chose to separate the seconds and
milliseconds with a colon (':'), rather than a dot ('.')? A few users of
tds_fdw recently ran into issues with this:

https://github.com/GeoffMontee/tds_fdw/issues/13

Because of the ISO 8601 standard, I think most applications expect a dot
separator between seconds and milliseconds.

http://en.wikipedia.org/wiki/ISO_8601

These days, it may make sense to use ISO 8601 as the default "date format",
since it is pretty universal. If FreeTDS is going to have a new release
soon, maybe it would be worth changing the default date format?

Thanks,

Geoff Montee