A 70mm blow up? Are you sure? As far as I know, JP never had any 70mm prints struck, unless it was some sort of one off thing. That'd mean it was in 6 track mag. Based on all the things I've ever seen, 70mm prints were never struck. Had DTS not been ready, I'm sure we would might have seen 70mm 6 track prints struck.
This of course is all stateside.