Just a couple of recoomendations if I may:
DON'T use boiling water - hot - yes, but boiling can damage the liner.
I'd advise against installing liner lock around the entire perimeter, if it's holding on it's own, great, once you install liner lock, you're stretching something that didn't need it in the first place and risking a crack in the receiver channel as well. Remember that the stuff is all older and has been exposed to UV rays for a long time now, UV rays trend to dry out plastics, making them brittle and the adding of liner lock can split a perfectly good portion of your receiver channel, so unless it really needs it, I'd be leaving it alone.