McGarrett's Silverado Crew Cab truck seen during the epilogue has the license plate F6-3958 - this was the same plate number used on the original series on McGarrett's Mercury Park Lane and Marquis sedans used throughout the series run.
"Ka Hakaka Maika'i" is Hawaiian for The Good Fight
Kensi's trip to Hawaii occurs between the NCIS: Los Angeles (2009) episodes Sacrifice (2011) and Lone Wolf (2011).