Ya, most laptops put the initial two ports under the keyboard, so not so easy or advisable to access them. So, when you first buy a laptop, know how much ram you want to get, best to get two 8GB dimms just in case. Although, even if you have 2 4GM dimms, you can still go up to 16 which really should be enough for anyone.
Of course, the real issue of not being able to access the other dimms so easy is that you can see their #'s so you can get the exact equivalent ram to prevent potential issues if you get the wrong expansion ram.