Yes, vernal equinox point is the starting point, the origin of the celestial coordinate system.
It is also worth mentioning, that the local sideral time is actually the time elapsed since the vernal equinox point crossed the local meridian.
BTW, this is the historical reason why RA is expressed in time units and not in angle: in the past RA of the object was measured with the help of a "Meridian instrument" (
http://en.wikipedia.org/wiki/Transit_instrument).
This was a telescope mounted such that it could move only in altitude. The Azimuth was fixed and oriented in South-North direction.
Astronomer would measure the exact time of passing of object over the centre of the field of view (with the help of cross hairs in the eyepiece).
The local sideral time of that passage was actually RA of the object
NB: 24h of sideral time is the time Earth takes for one rotation against stars - and this time is 3m 56s shorter than solar day.