Al Gore is a lifetime member. It's honorary and was given back in the early 80s.
The NRA is about supporting the 2nd amendment so I am sure there are democrats who support the cause and are members. There are a lot of democrats out there who don't support the democrats' platform they just can't bring themselves to become republicans. Particularly here in the south, I live in Noth Carolina.
Frankly, I don't think either party really serves the needs of the people. Since I believe in the Constituion and 2nd ammendment is the one that protects all the others I am pretty much a one issue voter. I vote for the one that is going to protect our firearms rights regardless of party.
There is a great group here in NC called Grass Roots North Carolina that keeps a close I eye on everyones voting record on the isuue and makes recommendations on there stance on firearms.