Probably will not help but if you go to
http://www.briggsandstratton.com/engines/support/operators-manuals/ and put in the model and type code seperated by a - , you will get the parts listing manual for the engine.
If it was an iron bore motor it would probably have an I/C sticker on the motor somewhere.
Are you just curious or do you think it might need some attention. Some things are best left alone. A head gasket will cost you about $10 its not OHV so it wouldnt be hard to find out about the bore.
Id say its not iron lined.
Bob.
