This is a question about the period of 1948-2017 - up until, but not including, the presidency of Donald Trump.
During this period, had the USA ever officially, explicitly, recognized West Jeruslaem as being Israeli sovereign territory?
Neither before nor during. The president's tweets and press conferences do not constitute a formal recognition. The state department has published a map U.S. Relations With Israel which says:
The United States recognized Jerusalem as the capital of Israel in 2017 without taking a position on the specific boundaries of Israeli sovereignty.
As such it is rather amorphous and not explicit.