So premarket is now available for OTC stocks, with the market opening at 13:30 currently (to be extended to 13:00).
However there is no reflection of this in the UI, no delineation between premarket and normal market open at 14:30.
This will almost certainly result in lots of users making trades premarket without realising it, when the market is much more volatile.
I have added a feature request for this here Please like or comment on this if you would like to see it implemented.