To be perfectly honest - and to run the risk of sounding like an amateur - I don't know. The sleeves are certainly "folded in" about 1 1/2 inches. If that's a sign that they can be "let out", then I imagine they can be.
I apologize. I've just recently had to enter the world of proper men's fashions and am still learning the ropes. Hence the reason for my averting to the previous sales thread for proper measurements and such.