Too many problems
Lets take it one by one
if a person having a work ex of 2-3 years in IT industry will he have a better chance of getting placed , is work ex very much required in MBA systems as it a mix of managerial skill + technological kownledge . and i think a person who has worked in IT industry, he has definitely worked on projects , he will have better idea of which technical thinks to be done in much efficient way than a fresher ,which technology should be implemented etc .
Whatever you wrote in bold is correct
But there is one myth regarding placements in IT companies.. A fresher and work ex with Systems MBA can probably get same job profile .. but as you already said that a work ex guy would apply his skills far more better than a fresher. This in no way means freshers cant do work at par, they are generally much better than work ex guys.

And if a conpany requires only work ex people for a specific profile then they wont look for freshers.. so its on case to case basis.
But just a second, why worry about specialization right now??
currently i am not having any job offer at hand and looking to give cat 2009.
Better prepare hard for CAT, crakc it, convert GD PI and while selecting a college you can think about specialization. Its too early for that. All the best