The IP used for the JSC was not made in 1985. It was made, at the very latest, in 1982, because it is the same source used for the early video releases.

Also, the JSC IP and Technidisc/GOUT IP can't be the same, because the latter source lacks the glue marks at almost every cut.

Finally, wouldn't an IP made in 1985 have been on some kind of low-fade stock? Supposedly, the 97 SEs of Empire and Jedi came from interpositives, and if they were usable in 1997, that must mean that they hadn't faded. (Remember, the original was the only big restoration project of the three.)