When Barnaby and J.R. are first discussing the case, J.R. says Gibson got away with $500,000 in gold coin. When Gibson/Simmons is confessing to his wife he says it was "a quarter-million".
J.R. is in a phone booth talking to Barnaby and watching Jordan (William Smithers) from across a city street, no more than 70-feet away. Easily within viewing distance, and completely visible to Jordan who is all but facing the phone booth. At one point J.R. even uses binoculars to see better, but it's just not necessary and makes it even more likely Jordan would have seen him.