He definitely worked on his shot in the year following their cup win, but that's only part of the reason why his goals number spiked. He openly said he wanted to take more shots to the net. The results speak for themselves.
2007-2008: 53 GP, 24 goals, 3.26 SH/G
2008-2009: 77 GP, 33 goals, 3.09 SH/G
2009-2010: 81 GP, 51 goals, 3.70 SH/G
2010-2011: 41 GP, 32 goals, 3.93 SH/G
Not a coincidence all of his SH/G averages directly line up with his goal pace in each of these years. I believe it was as much of a personal commitment to score more goals as it was about improving his shot. As I said, 39 goals at 18 years would be considered insane for any rookie out there.