I bought one of these decks around 2006. I sent email to B&O support and they actually posted me a paper-photocopy with a hand-signed cover sheet, good times (I wonder if they would even bother to reply about something this vintage any more!).
Here are some pics of the manual. I guess I should scan it, but I can't do it until I return to work in couple of weeks. Note that the numbering of items refers to two set of pictures and it is somewhat cryptic at times.
What you described sounds correct about the recording. I think the rec L and R buttons should lock down and the two red recoding lamps below the meters should light up when in record mode. The 2/4 is for selecting playback/recording of 2-track or playback-only 4-track. The heads in these are unfortunately known to go open-circuit and I believe my deck had that too, not sure if it was 2/4-track playback head so not completely unusable but limiting.
Location: Helsinki - Finland
"Bang & Olufsen - A Life Less Ordinary" // "It's not magic, it's the Bang & Olufsen link system" // "It takes more upon itself, asks less of you. And a natural consequence of this is the simple and striking design. The true harmony of form and function spells beauty in any language"