I rather suspect that many who tend toward more leftist causes but are from more moderate to conservative states (such as Reid from NV and one of my own Senators, McCaskill from MO) will mouth support for new measures to assuage their base but send back channel messages that they REALLY don't want to have to see one come up for a vote.
Reid is going to be a tough one to pin down on this subject. Traditionally he's been pro-2A, but there have been rumblings that his stance may have softened. With his position he's also going to be extremely important if and when any legislation comes down the pipe. I know he's gotten at least one letter expressing concern over any future gun control legislation, I can only hope mine is one of many from my state.