This is the cross member that is used with the convertible frame. May be part number 9798132 at least that's one number. Uses cushions on the ends and is 48" wide.
I have one that has had solid plates welded to the ends in place of the rubber pads . Ran on a 68 GS 400 conv.for decades. I can get pics if interested next week. As it’s in storage. Can be delivered to Nats. $50.00 takes it.
If you don't mind drilling a hole to make it a BBB,for the brake cable,this one is out of a GS,no rust at the original ends,and it comes with the rubbers and metal plate and the long bracket to hook up the hand cable.Bruno.