Been here, done this. All I can tell you is to make sure you got all of the nest out of the bottom of the cowl. I can recall sticking the vacuum cleaner down there. It had been there so long it rotted a hole in the bottom of the cowl. Had it patched years ago, and all is well.
I bought mine direct from Kee, and I'm pleased with it. I had it professionally installed before I shipped the car as the original one was toast. Pic is in my signature. So far, so good.
If you're looking for a nice rear seat for a '68 Newport, I have one complete, top and bottom cushion, in great shape in Western Massachusetts. Send me a note if you're interested.
Finally saw this car for the first time in a long time the other day, and the pics after clean up don't do it justice. I love VIP's and I love turquoise, and 383 and A/C don't hurt either.