Do you own a strait edge and set of feeler gauges.
You can check this yourself just like the machine shop does, its easy.
Can you feel any edge that you can catch your finger nail on?
Did you check the block. Very common to be pitted in front and rear where the gasket blew. Look right at where the head gasket sealing ring was.
I have fixed this with jb weld before. I know it sounds bad, but My son has been driving on his for two years now with no problems.