What clutch was in it and what are you going to put in it? If it has a step height it needs to be right or it will throw off pressure plate performance. Not sure what the other places are using, but if it's not surface ground it's not the right way to do it. Turning it on a lathe would leave a directional finish.
A place in Waterloo (clutch masters) does them for me on a surface grinder. If it's flat and just has some heat marks on it from a organic disk you can get away with scuffing it up using a die grinder and abrasive pad. I'd want to look at the flywheel though before doing something like that.