The pictures indicate that it is a left shoulder bag, just like every other 'sling' ever made.
Is there a D-ring on the other corner to allow right shoulder use?
yes, you can wear it either way. there are rings on both sides.
also in the product description on Amazon:
Amazon.com: Solo Storm Collection Universal 10-Inch Tablet Sling (STM751-4): Computers & Accessories
"Padded adjustable sling strap can be clipped for left or right side use"