Haven't ever heard of it being a problem. Is this the first time the engine was apart? Could it be that someone had it apart before and painted it? Looks like you have an interesting job cleaning the paint swarf inside that block. Elbow grease or light sandblasting?
The head and lower case are fine. I spent 3 days cleaning the powder coat/paint overspray out of the upper case. Waiting on new gaskets from the powers that be. Then on to reassembly