But what about the connectors? In the 2010 Mini, the HDD and DVD connectors are located side by side, but it's rather difficult to mistakenly swap them, though.
In 2010 the Unibody Mac Mini came out which is the design you're talking about. The 2009 was the old style and completely different inside.
Those models had a bay the HDD sat in with an interconnect board for the HDD and an interconnect board for the Superdrive that are completely different.