Early Block I was mostly used for testing. If you're just concerned with the first satellite launch, ehhhh, sure. As a useable global system it was much later.

Early Block I was mostly used for testing. If you're just concerned with the first satellite launch, ehhhh, sure. As a useable global system it was much later. "The GPS project was launched in the United States in 1973 to overcome the limitations of previous navigation systems,[15] combining ideas from several predecessors, including classified engineering design studies from the 1960s. The U.S. Department of Defense developed the system, which originally used 24 satellites, for use by the United States military, and became fully operational in 1993. Civilian use was allowed from the 1980s. " Here's the current list, marked by launch date and Block: https://en.wikipedia.org/wiki/List_of_GPS_satellites https://en.wikipedia.org/wiki/List_of_GPS_satellites