matic22
Ancient Mariner
Could be a loaned prototype. In the pre Steve Vai JEM days, Ibanez was quite desperate to land endorsers and was lending them guitars. Sometimes they only played them at Japanese shows. I think there was a similar case with Ace Frehley a few years earlier.It has been used at least once in concert.
EDIT : This is Beast On The Road tour, but the Ibanez RS315 was released in 1983. In 1982 Adrian and Davey were sponsored by Ibanez, this is probably a prototype model ?
Ibanez was producing quality Explorer copies (called Destroyers) in the late 70's and they were actually better than Gibsons at the time. One was famously used by Edward on more than half of VH I. So, as the tradition goes, if a copy is better than the original, a lawsuit happens. So, Ibanez changed the design to Destroyer II, but only produced higher-quality ones for the Japanese market (Adrian's is one of them). Why they did so is beyond me.
There were also some obscure models like the Steve Lukather signature, despite him rarely touching one and preferring his Valley Arts Robot at that time. Mid 80's were strange endorsement-wise, especially at Ibanez. And then in 1987 the JEM and RG happened. Rest is history.
So, in short, I'd say it's a loaned prototype. Also, if I see correctly, it's a hardtail. Adrian's has a tremolo.