The movie doesn't really specify which agency Loginov is with, and I don't remember if the novel did either. Though in the movie, when Ramius asks the Political Officer how many spies are on the ship, he replies with "if the KGB or GRU have placed agents aboard, they wouldn't have told me." So, there does seem to be a 50/50 chance that Loginov could have been KGB or GRU.
Given the level of mistrust baked into the Soviet System, it wouldn't even surprise me if multiple agencies had agents aboard to keep an eye on each other, as well as Red October's crew.
I too can't remember if the novel specifies him as being GRU (It's been a while), but if it didn't, I think it may have been mentioned at another point.
I went in at the end of 1976 a month before the election between Ford and Carter. Voted in the presidential election by absentee ballot in recruit training, and served under Presidents Ford (3 months), Carter (4 years) and Reagan (20 months). I went in as a Nuc starting as Seaman (E3) in boot camp. Middle of recruit training it was changed to Fireman and I was going to Basic Electricity/Electronics and EM "A" school. If it wasn't for Nuc School they would have changed my rating to Sonar Tech because of my Hearing tests in recruit training. They gave me the hearing test 5 times. I was a push button EM3 (@7 months in service) at the end of EM "A" school. I took the test for EM2 at Ballston Spa, NY D1G Prototype. The minimum score was "Pass" on the test. I made EM2 two weeks after I reported to the ship (@20 months in service). On the ship I took the Test for EM1 and advanced a year before the end of my 6 year enlistment. The EM rating advanced quickly from E4 through E6 because they always needed more Electrician's Mates in the rating than the number that took and passed the test. From what I saw, the engineering rates of Engineman and Machinist Mate also advanced quickly as well. This was in the Cold War peace time Navy under Carter, and before Reagan's ship expansion program started.
A bit of jokey simplification on my part. Probably should have used an emoticon... Still your anecdote supports the point I was responding to: Jonesy being able to go from E-3 to E-5 on the one sub. Of course, the Navy is always updating requirements. Something I recently read: "Sailors will be advanced from E-1 to E-4 based on time-in-service (TIS). Sailors not in an accelerated advancement program will advance to Petty Officer 3rd Class based on time-in-service only." -source (pdf) Apparently, E-4 is the new E-3.
2.5 years to make E-4, most conventional engineering ratings and strikers made it in less time than that when I was in. I had to wait 2.5 months after recruit training to start BE/E school, or I would have made EM3 in 4.5 months. But like you said in an earlier post. USN enlisted use the term rate instead of rank. Rating is enlisted specialty (example Electrician's Mate (EM)) Rate is enlisted specialty + pay grade (example EM1) Rank is the term used only for commissioned officers in the USN. As far as Warrant Officers, the USN only has Chief Warrant Officers (CWO2-CWO5). The USN skips Warrant Officer (CWO1) pay grade. At least they did back when I was in 40+ years ago.