Yes, and that would be easy to add, I may do that for my site.
In the forum it calls a function that calls a function; it checks to see how many seconds from now; and displays either the minutes, hours, or days. Easy enough to keep the minutes and hours and change the days to post date, or even allow a few days to past before post date is presented. The timestamp is passed to the orca date function which calls another function to get the aging and that is returned. Check the timestamp for the amount of ageing and if beyond what you want for ageing, then call your code, else allow it to call the original ageing function.
For the forum, the function for orca date is in /modules/boonex/forum/inc/util.php.
For blog posts, the code in in the blog module; I would assume each module is handling its own date.