The 30 threshold has always been permanently displaced about 30 metres from the physical end of the tarmac, or it has for at least the last 40 years.
That would take the displaced threshold to 1982 and I can tell you from personal experience that there was no displaced threshold back then or even for a good number of years afterwards. I noticed the flash fire station in the picture so maybe the threshold was moved when the old brick one was replaced.