2007 accord head gasket problems

Hi need some advice.
I just recently had problems with my V6 accord, is been overheating, I just know that is the head gasket because it has all symptoms, creamy appearance in engine oil cap. vapor and the end pipes after hours of running and multiple misfire, no thermostat and still overheating with no leakages.

I add a block sealer and now the car is working fine (Block Seal, Head Gasket Repair, Bar's Leaks brand).

I would like to replace the head gasket in my V6, but I was told that I need to the surface finish to flat the head and in the lower part too (block), is this correct?
I know that this must be done in the upper part (head) but never heard that this must be done also in the lower part (block).

I have a 2007 accord V6 Engine 4 door sedan SE. need advice.

Thanks

yes i think you can that. but i have not tried any of this .but read a lot about this..