Their is a lot of incorrect information going around about this. To clear it I I have a quote from Steven Read via twitter posted 2 days ago:
FAQ: if you played this weekend you do NOT need to uninstall the
#SWTOR client. We are planning to patch it to Early Game Access / Live.
This information is also repeated in this official post on the SWTOR site here:
http://www.swtor.com/community/showthread.php?t=687631So to answer your question, no it's not the release build but it will patch to the correct version on launch day. Downloading it now will save you time and allow you to avoid the rush of full client downloads when the final vers is released.
Please keep in mind that this could all change between now and launch, just because a dev says it can be patched don't mean that is what will happen. :P