Yes, you need the gasket or oil and water may get mixed up.
When you disassemble one of those old irons the verry thin paper gasket usualy comes of as a part of the gunk that was builded up during the years.
On the other hand it is possible that someone forgot to put one in at the last overhaul.
however - put it in.
Oh, some manufactors sale 235 gasket sets that match several years. I had to cut a portion out of my front plate cover gasket at the bump close to the oil snooze (to oil the cam gear). Make sure it fits or cut it to fit, otherwise it may block a oil passage or - even worse - a peace can come of when wet and gets into the engine.
Hope that helps, Frank
