Yes, he is.
Some bills Rand has sponsored:
Cut Federal Spending Act of 2011 (S.162): proposed to cut $500 billion in federal spending in FY2011.
Federal Reserve Transparency Act of 2011 (S.202): the Senate duplicate version of Ron Paul's House bill (H.R.459), requiring a full audit of the Fed before the end of 2012.
Fourth Amendment Restoration Act (S.1070): a little bit complicated, since it amends a lot of existing law, but in essence it limits the ability of the federal government to conduct Unconstitutional searches
A bill to authorize the interstate traffic of unpasteurized milk and milk products that are packaged for direct human consumption (S.1955): ...self explanatory
A Bill to Permit Voluntary Economic Activity (S.2269): "Prohibits the Sherman Act, the Clayton Act, and section 5 of the Federal Trade Commission Act from being construed as prohibiting, banning, or otherwise extending to any voluntary economic coordination, cooperation, agreement, or other association, compact, contract, or covenant entered into by or between any individual or group of individuals."
Preserving Freedom from Unwarranted Surveillance Act of 2012 (S.3287): Requires that a warrant be obtained to use a drone for domestic surveillance
A bill to require security screening of passengers at airports to be carried out by private screening companies, and for other purposes (S.3303): ...self explanatory
A bill to provide limitations on United States assistance, and for other purposes (S.3576): cuts foreign aid to Egypt, Pakistan, and Libya