If the answer is no, then it will fly at FL280 or 430? Or it will fly within RVSM airspace with vertical separation of 2000?
Ensure non-RVSM aircraft are not permitted in RVSM airspace unless they meet the criteria of excepted aircraft and are previously approved by the operations supervisor/CIC. The following aircraft are excepted: DoD, DoD-certified aircraft operated by NASA (T38, F15, F18, WB57, S3, and U2 aircraft only), MEDEVAC, manufacturer aircraft being flown for development/certification, and Foreign State aircraft. These exceptions are accommodated on a workload or traffic-permitting basis.
The Chicago Convention, which established ICAO, does not apply to State or military aircraft. This includes the restriction on aircraft that can operate in RVSM airspace. From an ICAO working paper:
The Convention on International Civil Aviation (Chicago Convention) and its Annexes provide the legal and operational framework for Member States, inter alia, to operate aircraft in airspace where a reduced vertical separation minimum (RVSM) is applied. The Convention shall be applicable only to civil aircraft, and shall not be applicable to State aircraft.
States are free to apply regulations on their own State aircraft, which may or may not permit them to operate in RVSM airspace.