customer's order invoice purchase date -- can I add the time too?

i was wondering if there'll be any advice offered for this help needed.

at top-right corner of customer's order invoice, there's purchase date, instead of the date only, could it display the date and time together? if so, how?

advice on this help needed is highly appreciated.

I would like to know this as well. Have searched the forum and found no answers.

This may not be the best way to do it but worked for me:

/admin/includes/languages/english.php

I changed:

define('DATE_FORMAT_LONG', '%A %d %B, %Y');

to:

define('DATE_FORMAT_LONG', '%A %d %B, %Y, %I:%M %p');

This will change order date to also display time on the orders page where zen_date_long is called. (This is good for my store because we do a lot of time-sensitive orders and time of order is important.)

The same can be done on the catalog end to display the time in customer order history.

PHP Time/Date format:
http://php.net/manual/en/function.strftime.php

If you have any concern about where else this might show up, you can search in Tools > Developers Toolkit. Paste DATE_FORMAT_LONG in the lower left box, select all files - catalog and search. This will show you all files where that format is used.
You might want to do the same for zen_date_long.