The scuttlebutt is that buffalo as a verb was only attested very briefly in upstate New York and the Midwest for a brief period of time in the early 1900s. It never spread nationally, and definitely not internationally.

However, checking Google ngrams shows that “he buffaloed” and “was buffaloed”, (to ensure it’s being used idiomatically as a verb and not just in the famous example sentence) emerged in 1900, peaked in the 1950s, but has sustained small but constant use in published print since then. I was actually expecting the ngram to rapidly drop off and never recover… shocked to see that some people still use it as a real phrase.