RT9840 suggests NMB (RT stands for Right Touch). So far as we know, the only mechanical keyboards from NMB are the 8000 series. I am not aware Microsoft have ever sold anything but rubber dome, and looking at its cheesy curved design, no, not likely to be mechanical : )
It will be rubber dome over membrane, but whether it's full travel, reduced travel, or scissor switch, I don't know. From the looks of it, scissor is pretty unlikely.
Just looks like another mediocre rubber dome like any other. Hopefully it's better than the Dell RT7D50 (not a typical NMB model number) which is truly horrible. Microsoft rubber dome keyboards are typically middle-of-the-road, neither good nor bad, but it depends on the OEM, the phase of the moon, and how many times China has retooled since the last batch (and indeed how many times it's changed factory since last time).
That's what makes rubber dome so awful: the utter lack of consistency even within the same product range: for example, the basic Dell KB1421 is from an unidentifiable OEM, but feels very good, while the KB522 multimedia equivalent is from Logitech and feels terribad.