boom of the 1950s and '60s was made possible by i.a. the Marshal Plan and Gasarbeiter from Yugoslvaia and Muslim Turkey
no. From Bundeszentrale für Politische Bildung, a state run agency: bpb.de/internationales/europa/tuerkei/184981/gastarbeit:
They say that until 1968, there were only around 150 thousand Turks in Germany and only then increased drastically and 1972 there were already 453 thousand. Up until then, Italians were the biggest group of immigrants.
Immigrants from former Yugo are not even mentioned in any statistics. How could mass migration from behind the iron wall even have been possible pre-1989?
Anyway, when the Turks came in droves, the boom was already in its final stages and in the later 70s, severe recessions hit Germany. While the number of immigrants continued to rise, employment of them stagnated:
but before mid-1965, foreign immigration was close to non-existant, esp. from non-european sources.
The most important immigration contingent in the boom years (1949 onward) came - until 1961 - from East Germany:
from 1949-1961, a total of 2,7 million came, 100% ethnic Germans fleeing communism.
For sure, the Turks that came in the late 60s did contribute well to the German economy, although on a minuscule level. They had to, because they could only get into Germany if they already had a signed work contract and social security was still in its infancy. And even if they were theoretically "muslim", they were not showing it. You will have a hard time finding a veiled women on pictures of the 70s and 80s in Germany.