WTB Few HP 339a knobs and original paper user manual(s)

[smartins]

Want to buy one complete knob (knobs_01.jpg) in good condition, one set of metal ring with grey cap (knobs_02.jpg) or complete knob with these. I guess, should be same on some other HP gear or that era.
My 339a miss only these and other knobs are in near new condition (not burnt by sun or damaged in other ways), so, would be shame not to try find originals. 
May take some others as well as spare if not extreme expensive (like ones with big "lever").
Also looking for two knobs with transparent plastic ring in any condition (knobs_03.jpg) from any HP- for experiments to make transparent stickers with digits, as these, like on most devices that old, are faded away also on my 339a.

Also looking to get original manuals (must be at least 2 versions?). I will make good scans for free public access as well.