No it's not quite that easy.
The problems start when you add the extract to the flask. If you have 1 pt boiling or hot water in the flask, how do you add the dme? If you just try to pour it in, a lot of it will fall on the outside of the flask.
If you use a funnel, the steam from the hot water causes the dme to get wet and you end up with a sticky mess in the funnel.
If you overcome both of these problems, unless you are very careful, you will get a boil over.
I find it much easier to add the extract to water in a saucepan, and then pour through a funnel into the flask when it is mixed. You then need to be very careful about boil-overs (depending on the size of the flask).
As David said, if you're not using a stir plate, make it on Thursday or even Wednesday.