Correct!
The windmill was made from a No. 4 Meccano outfit produced around 1936.
Meccano can be dated with reasonable accuracy by looking at its colours.
Pre 1925 it was nickel plate,
c1925-1934 dark red and green,
c1934-1940 blue and gold,
(1940-46 Meccano not made due to the war)
c1946-1964 light red and green
1964-70 yellow, black and silver
1970-77 yellow, blue and silver
1977-79 yellow and irridescent blue