In the parts manual for the engine I'm rebuilding (Skoda Estelle/120, RWD, rear mounted engine) I see they list washers for all the head bolts. I have changed the way to secure the head against the block by means of studs instead, so the block (which is aluminum) won't have the threaded holes damaged by future works involving removing the head. In the manual they are described as "washers", the illustration looks like flat washers. I also see them in the Haynes manual.
My question is: Should I still use washers under the nuts there? This engine had none!