Ah, the early 747 landing gear. Anyone remember the MLG Load Evener system. A good idea that did not pan out in practice. Used to get worried when one showed up with a WLG/BLG pair adding up to the bare minimum (7.5inches??) wondering how the hell you were supposed service it a line station.
The throttle bar was only one of many quirks of the dreadful early JT9D. I did not mind the early entry into service issues the airframe had but the JT9D. destroyed whatever faith I had in P & W.
The Convair 880 (and presumably the 990) had a separate MLG Speedbrake Lever just behind the spoiler/speedbrake lever that enabled dropping the mains only for use as speedbrakes. Don't know if it was used much. I suspect the nose gear was not used due to the aft door being unable to handle the air loads.