Rather an unusual event apparently, as the production designers are famously anal about continuity, and period accuracy.
At minute 35-37 (as aired), Betty is in Dons home study, and very clearly behind her head, is an omnibus edition of the W.E.B. Griffin books "The Corps: Semper Fi", "A Call to Arms", and "Counterattack"; published in 1986, 1987, and 1990 respectively.
As it happens, I noticed because I own all of those books (and every other book Griffin has ever published under his own name).
Oh and there was one other thing; not anachronisms, but an irritating discontinuity all the same.
The trip to drop off the brother of Dons love interest.
Theoretically, Don was supposed to take the brother from Ossining NY, to Bedford, MA; but instead Don dropped him off "20 miles outside of Framingham".
As it happens, I'm from the Boston area, and in fact lived and worked in the next town over from Framingham for a while. I've driven from Framingham to New York city, and through upstate New York many times.
From Ossining to about 20 miles southwest of Framingham (say, the pike south of Westborough), is about a 3 hour drive with no traffic; maybe two and a half hours if you're lucky. To Bedford, it would be about another 45 minutes or so.
Somehow I don't think an almost 8 hour round trip including at least one fuel stop) would be in the cards after a full day at work (and all the alcohol consumed in said workday). Especially since he started sometime after dinner time, and in full darkness etc... and returned to spend the rest of the night with his girlfriend.
If the scene with Betty immediately following Dons return to his girlfriend was timeline correct, Don would have returned a few minutes before 2am.
Given that it is September in this episode, and we know Don takes the 6:45 train (mentioned in previous episodes; and according to interviews with the writers of the show, they checked timetables from 1963 to be accurate)) and arrived at the girlfriends house in full dark, the earliest he could have left with the brother would have been 8pm.
It is just barely possible that he could have made that trip from 8pm to 2am... just... but then the girlfriend would have known he didn't go all the way to Bedford. He would have had to have at least got a cup of coffee... or driven 100mph the whole way, and made at least TWO gas stops...
Other shows, I don't much care about that sort of thing; but for a show like Mad Men, which are obsessive about continuity and period accuracy... Seriously, they could have checked a map; or just chose a better location (there was a VA hospital in New Haven CT, only 90 minutes from Ossining).