Yes, it accounts for it:

> `AT TIME ZONE` applies specific rules for converting input values in
> smalldatetime, datetime and datetime2 data types, *that fall into an
> interval that is affected by the DST change*

As per the [MSDN article](https://msdn.microsoft.com/en-us/library/mt612795.aspx) on the expression. The `sys.time_zone_info` column supplies information on if the zone currently is in DST, but the article above indicates that the rules take into account DST given a specific date time value.