The two parts are basically the same. When you order online by system information, you are shown what we refer to as an “external” part number, in your case number CT4541069. It is a system specific number and is mapped exclusively to the Asus n550jv. The longer part number, BLS2C8G3N18AES4CEU, is the one that would you see printed on your module, and that is the actual module part number, or the "base" part number. You should have no issues if you order BLS2C8G3N18AES4CEU from the vendor in your area.