The GMO tour helps, except if you royally screw up. You still need your COs endorsement.
Publish!! The more articles in a peer reviewed journal, the better. Each article counts for a certain number of points towards the selection board. This can make up for a less than spectacular GPA/Board Scores. Voluntarily rotate in the residency program; some commands let their GMOs go for a couple of weeks to get "face time" in the programs. Helps with interviews. Being known in the department in a good way, can't hurt.
Do a search in the forums, someone posted all of the criteria that they score you with objectively.
99% sure you will need to do a Navy GMO, FS, or UMO tour.
Navy Radiology is currently competitive now...so good grades in college (yes, they look that far back), medical school, AOA, being a competent intern, and publishing helps...especially if you want to get in on your 1st try. If you're not most of these, you may possibly have to do another GMO tour. I've noticed it sometimes takes 2 GMO tours to get into the competitive fields in the Navy (Radiology, Derm, Optho). Overall, Navy Radiology is above average compared to the civilian world.
In my opinion, if you have the STATS, why not finish your commitment and apply for civilian Radiology residency. Once you graduate civilian residency, you're life is so much better (compared with Navy Rad attendings). You start making good $$$, have better hours, do not deploy, and deal with less BS. I know this one FS who finished his Navy commitment and started his Radiology residency at the UNIVERSITY OF PENNSYLVANIA!!! LUCKY GUY...he's got it made!!!