Here is some information for you to check out. A lot depends on the condition of the fabrics and the seams, especially with a front loading washer. I think I'd go with Orvus in the bathtub, just to be safe. Very nice top, it'll be stunning finished off. :-)
http://www.quilthistory.com/cleaning.htm
http://www.marilynquilts.com/id23.html
http://www.centerforthequilt.org/que...ry_soiled.html