I hope I don't seem too nitpicky about words and such, but Rand definitely contributed by turning them on to libertarianism. I think the vast majority of people that read Rand's fiction liked the laissez-faire themes, but I don't think they continue on to read Rand's non-fiction, though maybe they've read Capitalism: The Unknown Ideal. It's sort of like Milton Friedman and his contribution to libertarianism; lots of people have read Free to Choose, but they didn't all go on to be monetarists.
In so far as Objectivism has played a role in libertarian politics, I just don't see the influence anywhere. The major debates within the Libertarian Party in the 1970s, for example, were typically between the radical libertarians (Murray Rothbard, later joined by antiwar.com editor Justin Raimondo and others) and the minarchists/minimal-statists. Ed Clark, the Libertarian candidate in 1980, was part of the latter and characterized libertarianism as "low-tax liberalism." The disputes continued in the 80s and Clark and David Koch (of the Koch brothers) left the party. The party had more influence from the radicals in the 80s, culminating in the 1988 nomination of Ron Paul. The 90s and 2000s were uneventful on the national level and I don't think there was as enthusiasm within the party as there was in the 70s and 80s. The party's leadership has more and more started to cater to disaffected Republicans rather than the libertarian faithful. It's sad, and I think you can see the influence on the 2012 GOP nominations race as lots of libertarians are defecting to the GOP so they can vote for Ron Paul, and regardless of Paul wins or loses, I don't think a lot of people are going to switch back to the LP.
tl;dr version: Rand who? No Objectivist caucus in the LP.