A few months ago I flew GLA-DXB, and as it was my first flight on EK I particularly made a note of the aircraft registration, which was A6-ECS. I found out subsequently that this is a 3-class aircraft, while GLA is of course a 2-class route.

I am certain I got the reg correct, so is it likely that a 3-classer is sometimes substituted? I check this route regularly and noticed no repetition so far.

Not too important, but would satisfy my curiosity!