We do not recommend that you install gas meters indoors.  Under national code for all propane Lp and Natural gas, all meters are to be mounted outside the building with an appropriate shut off valve, for emergencies, prior to the gas line entry into the building.  In the absence of any state or local code enforcement, the national code for installation, testing, and final use of the meter will prevail, including the use of all materials in standards of the NFPA (U.S.) for safe and approved use.

It should be noted that in the event of a fire caused by gas, and if the meter is not properly installed, this fact could void any insurance claims.  If rural and on LP, the supplier will more than likely be happy to inspect the installation if requested.  In most U.S. cities, the gas company/or plumber, certified for gas systems, will do the final inspection and test. This is sometimes followed by the gas company notifying the code enforcement agency, who will green tag the installation for use. Or, if the system fails the inspection and/or pressure test, they will issue a red tag.

This from inspectapedia.com explains the issue:

"Gas meter location: gas meters are located outdoors except when special permission is given by the gas company. Indoor gas meters increase the risk of an indoor gas leak, require special venting, and can make it more dangerous to shut off gas in an emergency.”

The risk, as stated above, is indoor gas leaks. To minimize the risk, we recommend that all gas meters be installed outdoors. We recommend that your installation adhere to any local, state, and/or national codes in your jurisdiction.