Yup. Used mine with a Telkom and a CellC sim as a test, and both fired up. There's even a dual-sim menu to select your primary data sim, and also which sim is used to make calls.
I recall reading that the device does not support simultaneous use - probably only has 1 physical radio that is shared between the two sims. So you cannot e.g. conference call between networks.
But, 2 IMEI numbers - for sure. The sticker on the back of the device (and on the box) list both IMEI numbers.
PS: This is an awesome little phone. Only gripe is that it has a tendency to kill fitness apps randomly. I've lost a few runs where it just died halfway through. But sure I'll get to the bottom of that still - seems to be a general Huawei issue.