I too was always of the belief that axe (and hammer etc) heads, by convention, were stamped on the left side but I have seen too many right-stamped ones over the past couple of years (via pics on this forum) for this to have been universal or rigid practice. As they used to say about American cars during the 1960s; don't buy one that was made on a Monday. I suspect that more than a few distracted, sleepy, lazy, impaired or hung-over workers over the years omitted to properly orient some of the hundreds of newly-minted heads on the seemingly endless procession of goods on a monotonous assembly line before imparting the company stamp.
Sort of like rare Post Office misprints of letter stamps I guess a right stamped Black Raven should really command a collector's premium despite being an ordinary utility axe in every other respect.