Yes, the stock fan has thermal paste on it, therefore, when you put it on the cpu, you get thermal paste on your cpu. If you want to install a different cooler afterwards, you have to clean the older thermal paste off with alcohol.
If you are buying a brand new CPU, the CPU will be clean. No need of Alcohol. Alcohol is only used to clean the old thermal paste off, so you can apply a fresh coat.
If you are buying a brand new CPU, the CPU will be clean. No need of Alcohol. Alcohol is only used to clean the old thermal paste off, so you can apply a fresh coat.
What about if I install the stock fan onto it when it is outside of the case to test, then install the block inside the case. Do I need it now?
Yes, the stock fan has thermal paste on it, therefore, when you put it on the cpu, you get thermal paste on your cpu. If you want to install a different cooler afterwards, you have to clean the older thermal paste off with alcohol.