I do not think it will matter.
Before you buy the extra stick, do what you can to insure that it is a compatible upgrade.
Go to a site like Kingston, crucial, corsair and access their ram upgrade app.
Enter the make/model of your laptop.
You will get a list of compatible and supported upgrades.
The new ram must be the same speed, voltage and cas specs.
You can use cpu-Z to see exactly the specs you have now.
the matching 2gb in each channel will operate in dual channel mode, a very good thing for integrated graphics. The odd 2gb will be in single channel mode.