Hi Vinod Nayak: 
Thank a lot for the two guides on how to find the MSL and how to change from NV to RUIM. I was searching for days on how to get my LS990 working in Japan and I am happy to say that I am a happy camper today thanks to you. Please note that I made this post on XDA so that many others in my situation find some joy this holiday season. I hope you don't mind. 
http://forum.xda-developers.com/sprint-lg-g3/general/unlock-sprint-ls990-cdma-carrier-t2985523 
FYI, I only get 3G signal/speeds with KDDI after setting up an LTE APN. Is there a way to get actual LTE speeds with the LS990 with KDDI Japan? 
Thanks again for all the help!! 
Dan