Let me give you my personal experience with surgery and with DoDMERB.
I had the surgery in 1979 after three dislocations. The surgery was performed by one of the developers of the procedure. At that time, most surgeons were still using pins. Those who got the pins definitely had reduced range of motion. At that time, orthos seemed more reluctant to cut. Mine wanted to see a pattern and considered surgery a last resort. I knew kids who figured out to reduce (relocate) their own shoulders.
Within a couple of years I stopped worrying about the shoulder popping out and have stayed relatively active over the years. I have total range of motion and as part of a regular workout regime, I do push-ups and pull-ups to the point of exhaustion.
You will have the advantage of a smaller scar and infinitely better follow-up physical therapy than I had.
DS #2 applied for NROTC scholarship in Nov of senior year. Was hit in the eye with a soccer ball Thanksgiving week. Immediately saw optho. There was trauma to the eye, but no surgery. Treatment was to avoid any possible eye trauma for one year. No LAX, no sledding, no skiing.
DS received scholarship notification in Feb. Immediately started DoDMERB. Passed all aspects of physical. In April, received request for more info about the eye. In May, informed he needed waiver for the eye, which would not be granted at the earliest, until Optho cleared him. The Optho said one year from date of injury, but ended up 14 months after injury.
I am no physician but the constant theme with DoDMERB is they do not want anyone with a medical condition which would disqualify the candidate or create a financial liability for the military later. Ergo, if you have an injury, you must be fully recovered. A dislocated, unrepaired shoulder would be suspect. If you have/had surgery, you must be fully recovered, which means it would take potentially months after the surgery to determine if there was full recovery.
As Ortho if he/she has any experience with military or DoDMERB.
Bottomline, if you get the surgery, get it sooner rather than later in order to be fully recovered.
Best of luck!