See that bolt jammed into the oil injection spout? Definitely a stock Blaster carb.
This is why when someone is trying to identify a carb, and someone suggests to measure it, it's a fail. The advertised carb size is only right next to the slide. Most people don't have the tools necessary to measure the carb bore that far in. For most carbs, the best way to identify the size is by doing a Google search for the letters and numbers stamped into the carb body.
For example, 70R is a Keihin 35mm PWK.