I agree with your statement, but I feel like it's rather splitting hairs in terms of the entire conversation. Both the Bolsheviks and Mensheviks came out of Iskra (and it's impossible to describe Lenin without it), and reading culture very much fueled the rise of the vanguard and Lenin's immense popularity. The narrative passing from Lenin to Stalin was also driven by essays in newspapers by political figures. Reading culture was inseparable from political culture at the time!