The following links lead to "old" posts about RTEXT.
RTEXT is "desiel" based ...
And will run provided you're in AutoCAD 2000i and above.
I believe for A2Ki you need the "Expres Tools" but after that ... A2K2 & 2004 come with this support automatically.
Of course you need to insert the text into each file before plotting. But once done, it will automatically update.
RTEXT DATE & TIME
thread555-32562
thread555-48232
RTEXT - MORE VARIABLES
thread555-28837
thread555-29186
thread555-52124
You could also enable the time stamp within the plot properties dialog box & then run a batch plot.
Here is a diesel string that I use to give the drawing path and name, the layout name, the date plotted and the user name. This is saved as a seperate drawing and inserted as a block into the title block drawing which is then inserted into the layout of a drawing in paperspace. It works brill for people asking what the drawing was and where!!!
Use RTEXT and enter this string (RTEXT is only in the express tools upto 2004 I belive, then included??)