For sure a dedicated specialization phase can bring some results in 3 months. I just think this dude might be better served thinking more long term. Sort out the problem if the legs are on the smaller side, but I'd make it part of the bigger picture rather than the primary focus for now.
Ha, no way did I mean to talk you out of bulking. Like I said, I just think you're still at a point where you can make more/bigger/better improvements by still focusing on the mid-to-long term instead of breaking things into too many different short term steps.
Reminds me of something I forgot to address before:
If you can get more specific with your goals (who you want to look like; what you want to weigh; what your squat, bench, deadlift, and overhead press will be; etc.), then you'll be able to figure out an even better plan to get there.