yup thats it. definitely a sandcast wheel.
what are the effects of smaller front wheel?- is the difference between 18 and 19 enough that it was offered as an option to pick one or the other?
That's right, the automatics had 19" aluminum wheels, same as the 75-76 GL1000. Quite nice, actually, looks like a Borrani.
A smaller front wheel allows for quicker turn-in. A lot of the European bikes from the 70s had 18 inch front wheels... It would actually make a great wheel for a cafe racer, which, after all, was a Euro thing originally.