After doing only a bit of research, it can easily be concluded that he was not the Kalki avatar.
1. The Kalki Avatar would be born in the Shambhala village
2. The Kalki avatar would come at the end of the Kali Yuga, which is a bit less than 427,000 years from now.
3. After the Kalki avatar comes, the present age will be banished, and the golden age will begin
4. The Kalki Avatar is an incarnation of Vishnu, not a prophet
5. The Kalki Avatar, according to the scriptures will appear when everyone is atheist, no one gives up anything (for anyone or anything), and bad people rule the government
6. The Kalki Avatar will kill millions of bad people
This description fits Muhammad in no way.