[SQL] Object create date

[Fernando Hevia]

Hi list,
 
I'm having a hard time trying to find out if the latest patches have been 
applied to my application (uses lots of pgplsql functions).
Does Postgres store creation date and/or modification date for tables, 
functions and other objects?
It would help me a lot if I could query each object when it was created. Is 
this information available on 8.3? Where should I look?
 
Thanks,
Fernando