Oh, sorry. I was so focused on the ability to change the special effect that
I missed your underlying question.
There is a way to change default format for each object type, but (at least
with Access 2003 that I am using), I do not see Special Effects as a
configurable option for buttons.
What happens if you copy the button from the sample database and paste it
into your database? Does it paste correctly, or does it assume the flat
effect? If it is correct, you might be able to change the default by doing
this:
Go to design view
Click the correctly-formatted button
Cick Format -> Set Control Defaults to get the default settings to match it.