The ESP Guitar Company

I've had (and loved dearly) an older LTD EC model. It's much heavier than the current EC-256 and has what appears to be a SD JB/59 combo especially made for ESP. Night and day from the Duncan Designed models. These sound like the originals. Anyone have a time frame these were made? Always wondered or am I just overlooking an ESP/LTD version of the Ibanez Wiki?