Not to be argumentative but....no actually originally 1970s it was an aqua color to go with the original RCA Space Mountain...I am absolutely positive of this.
original attraction key colors were a navy blue, orange and aqua... even the lights in the interior queue were a special order teal/aqua color.
over the years in repaints they lightened it up to a bluer tone... I have pictures of it somewhere...
1975:
Which also matched the trim around the satellite building: