Yup. Here's an excerpt from the museum's info.
The No. 1 XB-70 made its initial flight on September 21, 1964, and achieved Mach 3 flight on October 14, 1965. The No. 2 airplane first flew on July 17, 1965, but on June 8, 1966, it crashed following a mid-air collision. The No. 1 airplane continued in its research program until flown to the Museum on February 4, 1969.