Authorities did release the eligibility criteria for the Sponsored seats. Candidates must have qualified in NEETPG. Candidates who are working in a Govt. Organisation be it State/Central/Autonomous/PSU etc on a regular basis are eligible for Sponsored  seats. The official notification also doesn't mention any time. Now you did mention your rank but haven't mentioned whether you have qualified in NEETPG. This is an important criteria to be met.