ORAC
IIRC China negotiated (quietly) deals with Burma, Pakistan, Afghanistan and Iran in the pre 1962 period
The Indian case was negotiable but Nehru went public and would only negotiate if the CHinese gave him everything he wanted
Regretfully since the mid-80's China has taken a far more bellicose (and idiotic) approach to such matters (eg the 5/7/9/25...... dash line)