Condition Three carry (loaded magazine in gun, chamber empty) has been around since the dawn of the auto pistol. GI technique going back 100 years is (assuming right-handed shooter; vice versa for southpaws): draw pistol with right hand. Left hand comes down on top rear of slide, thumb on left of slide and four fingers on right side. Left hand racks slide sharply to rear and lets go. Can be accompanied by right hand reciprocally pushing frame forward to expedite the slide rack. Shooter, at least in the old days, finished with one-hand grasp in either "combat crouch" or "bullseye stance."
As I understand and have seen the Israeli technique taught, right handed shooter draws pistol in right hand and brings it to approximately center chest, top of slide usually tilted somewhat to the left. Left hand grabs slide at rear with fingers on left side of slide and thumb on right side. Gun hand pushes frame forward, support hand pulls back, releasing slide when it reaches its rearmost point. Shooter finishes with gun extended in one- OR two-hand stance, the latter usually Isosceles.
I'm not sure exactly when the latter technique was first developed, CB, though I've seen it for decades. Nor do I know of any one individual credited with developing it.
I haven't been everywhere, but the cops I met in Canada, Great Britain, Europe, and South Africa and South America all carried chamber loaded.
Hope that helps,