I was on the the same route dxb to pek on ek308 29th/aug.
I must say i was in for a suprise that day also. Checked-in at kuwait (J class) and was of course given 2 boarding passes, the DXB-PEK pass showed J seat 2K ?? i asked the counter what type of plane was the DXB-PEK, there replied 340-300.. hmmm interesting.. I thought to my self.. well 2k is first class (unless its a 2-class config).. whats going on.. I kept quiet.. and if it was a system mistake.. i'll happily take it.. (been a while since i was rewarded for the flights i take on emirates..)
Anyways.. reach DXB.. got 4 hours til the flight.. do the regular thing.. lounge and shop.. get to the gate.. the gate was changed.. have to trek to the beginning of T3.. reach there.. still havent started boarding.. i sit down.. boarding is called.. then i realize i fogot my mobile back the lounge.. so i ran there and back.. join the F/J que, only to notice someone else had simular boarding.. she was in J class with seat 2A.. hmm again..
Anyways.. the person head of me.. was in Y class but had sliver, so they scanned his boarding.. and they say we are upgrading you and your friend to J class ( apparently on the same booking)
I get on the plane.. and hold and behold.. its SUITES.. 340-500

abit old.. doors dont shut completely (at least mine didnt) i had to manually close the small gap..
It must have been my lucky day... cos i was so close to changing my flight in kuwait to the earlier DXB-PEK flight at 3am EK306 (normally a 777-200LR).
It seemed that NO ONE was on first class ticket... so all 12 Suites were upgrades. The disappoint aspect of the flight is that they werent giving us first class treatment.. saying that this is J class.. but i didnt complain and didnt make a difference to me.. as i was intending to sleep through the whole flight.. which i did..
sorry to hijack your post.. and kinda turn it into a trip report.. atleast alittle related.. hehe