It bolts into a lug the side of the block or crankcase.
Its a side valve, the head is about a 1" thick bit of aluminium. Thats it, nothing fancy.
Yes if it has the starter on top it will have a spacer.
If it has the starter on the side (pull up type), no spacer.
Yes the head bolt off a briggs the same as the one you are fixing. Its a little bit longer than it needs to be but will do the job.
Or if you ever had holdens or falcons you might find one or two that will work in your bolt bucket.