It should be a nice mower, Johno, provided it isn't too far gone. If the dimensions are OK and you go ahead with the re-ringing, we can talk about how you can break the glaze in the bore without going to the expense of buying a hone. Most likely I won't be the only member here with a pet method that has worked previously.
Note for B&S overhaulers: Briggs and Stratton recommend that you do not break the glaze of an aluminium bore, when replacing the rings:
http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/css/TM-5-4240-501-14P_250.htm
