If this is a first time for you, I suggest you take the block to an automotive machine shop and ask them to mic the bores for you to see if they can hone it and go with the standard pistons or if it has too much taper/out-of-round and will need to be bored to the next oversize. Trust me, whatever this costs will be cheap money spent. Tell them not to ridge ream it, just measure it and report what they find.

There will be no point in removing the ridge (which you can do yourself at home with the proper tool) if you have to bore the block anyway.