Help getting from ZVD to ZVG

First off.....I deal with Samsung devices and not very familiar with LG. Would like to get my wife's Sprint LG from ZVD to latest (assuming it is ZVG). I've spent some time reading forum posts and see plenty of "return G2 to stock" but it doesn't list what version of stock they are taking the device back too.

Assuming I have to get the bootloader and modem updated to lollipop, and use LG Flash Tool, what files do I need for this? Is there a stock 5.0.2 rom image somewhere?

Thanks.