Tell the truth now, or pay the piper later.
What will happen once you reveal this pertinent fact you will have to wait one year from the date of surgery. After the year you may then be re-examined & sent to ortho for a consult. The doc will take some x-rays & check your range of motion as well as strength. After that the medical waiver is then submitted & either approved or shot down. Don't be a fool. If you go to boot & that shoulder gives you a chronic problem & they examine it you will be screwed once they realize you had a surgical procedure you initially failed to mention.
I had problems with chronic anterior dislocations, no surgery though, and told them before enlisting. I did have problems with it & even dislocated it on the O-course. Despite this I still managed to make it and graduate with my platoon. I had surgery at Yokosuka Navy base while stationed at Camp Fuji, Japan and have had no problem since. In fact I just had my medical waiver approved for re-enlistment in the army so I'm speaking from recent experience. Don't screw up your future by lying now. Just be patient & do what it takes to fulfill your dream. Good luck!
:usmc: