Virtually impossible to tell visually since both can look very similar especially when young. Only wild Labiatus keep thier swollen lips and a lot of them will actually lose them after being in captivity a while. If I had to guess I would say Midas based on the higher profile but if you got them form a reputable source trust what they are.
Below is my F1 Labiatus from Jeff Rapps.... Clearly the lips are more fleshy... However, some Labs have more or indeed less pronounced lips and some Cits have more pronouced than some Labs. As suggested here, you can't put a finger on exactly which it is or whether it is infact a cross unless you know its exact origins.
This is my old pair of Midas from Rapps. My male on the left looks like a midas but my female could arguably look like a labiatus. However both are pure Midas. And these are young fish, both under 6in.