Yes it DOES happen. Even as I type there is someone I know doing a fastrack upgrade (boeing, airbus I dont know). It is not a sure thing though because it totally depends on the company so dont expect it. But you could ask in the interview what your chances are based on the demand for fleet upgrades.
Oh and please could you ask the interviewers if basic pay is going to increase due heavy inflation here in dubai and let us know what they say eh.
Happy New Year and good luck.