I don't know if the distortion would be less or not without that, or affect the tone, but if you're using the 741 then the 25pf cap doesn't belong. Remember overdrive and distortion are really the same thing. It's all in the marketing of a product. The 250/308 family of overdrives is actually based heavily on the MXR Distortion+ (as was the original bud box Ross Distortion) so that should tell you something. The circuit is the same, but the part values makes the tone slightly different sounding.
Also noticed your diodes are different too. The 250 and 308 just used two 1N4148 diodes. Using the other diode too probably does affect the flavor of distortion.