I figured that out after looking around indeed. Same as you my CPU is a 2cores/2threads so DMS is only showing 2C/2T.
For the serial I changed the last 5 digits. When I tried to register at Synology for the fun it showed up like a DS114 if I remember right.
So far, the only things that do not work (but this is registration related) is the QuickConnect functionality but it can easily be overcome by setting up a custom DDNS and the Push Notification to the DS Finder app. Those two can only work if the product is purchased and properly registered on Synology's website with a valid serial number.
I have also noticed something peculiar regarding the network interface. If I bond LAN 1 and LAN 2 then I will not see any activity at the Resource Monitor Network tab. The graph will remain totally flat even if I am uploading stuff to server. In fact, even without bonding, LAN 2 always remains flat although I have sent data to that network interface. Any ideas why?