Was messing around with my bueld.prop I think I need a LG LS620 stock recovery topic

I was messing around with the build.prop on my Boost LG Realm. As far as I know there is no way to make a backup to this phone, so I did the next best thing and made a copy of the build.prop and saved the original. Somehow though when I copied and pasted it back into sys file using ES explorer, something went terribly wrong. the phone gets a black screen of death right after the boot screen. I am able to get into the stock recovery, but no further. I'm thinking that a copy of the stock firmware is my only help but I can't find a copy of it anywhere. I do have a second Realm that is my son's that still works (probably because I haven't touched it yet) if that helps at all.

Haven't been around in a while few questions! topic

hello everyone, as title says im just ask and hope for a reply!
Once the boot-loader is unlocked can it be locked again?
Can i down grade my OS without rooting?
Whats the best Rom/kernel to put on this phone? (must have silent mode unlike lollipop-_-)