Moth3r said:
"Close the blast doors" was missing in the first 1977 run as well - it didn't appear until the mono mix, which was finished some time after the Dolby mixes. The 1981 print you saw probably had the original 1977 Dolby Stereo sound mix.
I saw SW three times in June 1977, and it had the "close the blast doors" line. That means I saw it in mono?