What contacts do the numbers on this DPDT relay refer to?
The diagram shows contacts in their normal state, and the slanting line shows the common contact. So you should be able to see that the pinout is:


Coil
NO1
COM1
NC1
NC2
COM2
NO2
Coil


You can't be sure which set of contacts is no. 1 and which is no. 2 but it doesn't matter as they're interchangeable.