Is it time to follow the smart money's lead?Oil prices have started bouncing higher,, but even before geopolitical developments resulted in a rebound, Wall Street's "smart money" apparently began increasing their positions in top oil and gas companies.At least, that's the takeaway, based on recent money manager accumulation of shares in Chevron (CVX +0.94%) since late last year.Chevron has been a top oil and gas stock for years, but today it offers an interesting value proposition. While Chevron stock may n ...