Manse Everard's Period

Poul Anderson's first Time Patrol, story, "Time Patrol":

was first published in The Magazine of Fantasy and Science Fiction in May 1955;

and was collected in - 

(i) Guardians of Time (Gollancz, London, 1961; Pan, London, 1964);

(ii) The Guardians of Time: First Complete Edition (TOR, New York, 1981), with an Afterword by Sandra Miesel;

(iii) Annals Of The Time Patrol (1983);

(iv) The Time Patrol (New York, 1991);

(v) Time Patrol (New York, 2006).

I have all the collections except (iii).

In (i), Manse Everard's class at the Time Patrol Academy are recruited from the period 1850 to 1975 and study the history, science, arts, philosophies, dialects and mannerisms of 1850-1975;

in (ii) and (iv), they are recruited from 1850 to 2000 and study the history etc of 1850-1975;

in (v), they are recruited from 1850 to 2000 and study the history etc of 1850-2000.

At the end of "Time Patrol," when Everard, having completed his first mission, returns home from 1944, "...a decade had passed." (Time Patrol, p. 53) This means that he was recruited in 1954, the year before publication of the story. This in turn means that he was mistaken to think "1957" when talking to Wanda in The Shield Of Time (New York, 1991), p. 32.

When based in 1954, Everard learns what is to him the future of the twentieth century:

"It was a peculiar feeling to read the headlines and know, more or less, what was coming next. It took the edge off, but added a sadness, for this was a tragic era." (Time Patrol, p. 17)

Gorbachev is mentioned in The Shield of Time but not before but we are to understand that Everard knew of him before.