Absolutely - at a minimum, a 1st LT, likely a Marine Captain (O-3). In that period, it took a minimum of 18 months to get through the jet training pipeline and get your wings, then another 6 months in the EA-6B "RAG" type training squadron before getting to a fleet squadron. By that time he would have been at least an O-2.
And as I sometimes like to pull the chain of my Marine friends - remember - Marine pilots are officially designated as "Naval Aviators" when they get their wings. They go through the Navy system, get the same exact training as their Navy cohorts. A certain percentage of flight instructors in ther Naval Air Training Command has to be Marine officers. The system has always worked well.
Yes in this time frame it was 18 months for any of the three pipelines. The program was flown by US Marines, US Navy and US Coast Guard. There were also some trainees from allied nations that went through the program. In the 60's, all the trainees would have been carrier qualified on the T-2C Buckeye.
An Aviation Cadets training would have started at one of 13 civilian ran schools where they would have been tested and then trained to fly and they would gain a GA type certification. This would be flown on the Beechcraft T-34B Mentor
Then from the introductory or elementary flight school, they proceed to Aviation Cadet Officers course which was a 13 week boot camp for wanna be jet jocks (this part of the training is portrayed in the movie An Officer and a Gentleman).
From there the newly commissioned officers, Ensigns and 2nd Lieutenants (0-1), were sent to either NAS Corpus Christie, Texas or to NAS Whiting Field (North), Florida to begin primary Student Flight Officer program. Here during the 60's, the training was flown on North American T-28B/C Trojan piston engine trainers, but in 1973, the Beechcraft T-34C Turbo Mentor was phased in. Also some pilots took the basic course at NAS Memphis.
From primary, those still in the Student Flight Officers course, were shifted to NAS Pensacola for basic and jet conversion training on North American T-2C Buckeye, here is where they really get a taste of naval aviation and carrier operations. By the end of the basic course all the nuggets to be were carrier qualified in fixed wing aircraft and had at least three traps and shots off the USS Lexington or the USS Antietam (if it was the early 60's). Once they finished basic course at NAS Pensacola, then the powers to be would decide what pipeline to drop them in.
If they were selected for carrier jet aviation (fighters or attack) then they stayed at NAS Pensacola for advanced training, and after 18 months they became Naval Aviators with the rank of Lieutenant (Junior Grade) or 1st Lieutenant (O-2). For the greater part of the decade, the advanced training was flown on the Grumman TF-9J Cougar, but 1968, the Douglas TA-4J became the advanced trainer.
Those selected for the rotary wing pipeline were sent back to NAS Whiting Field (South) for the primary helicopter training. Once they graduated that as O-2, they would receive their advanced training at their Fleet Readiness Squadron. Here, until 1969, the pilots were trained on the Bell TH-13M, until the phase in of the Bell TH-57 Sea Ranger.
Those selected for the land based aviation were sent to NAS Corpus Christie for multi engine training. The main birds here were T-39 Sabreliner, TS-2 Trackers and a few others. Again once they graduated as O-2 they were sent to Fleet Readiness Squadrons to complete training....
Regardless of the pipeline, before you reached the Fleet Readiness Squadrons, the "Nugget" had at least 18 months of training, some had more because of recycles due to illness or injury.
Up until the advanced phase of training everyone had to complete the same requirements.
or even better