Is bulkhead double skinned ?

I,m in the process off replacing front left outrigger on my 110 (bitch of a job). To improve access i've taken off the front wing and have noticed some corrosion on the bulhead just below the heater unit, what is puzzling is that there seems to be a double skin. Not sure if its because previous owner replaced front floor and dash wall and just welded it in on top of the old one. From various pictures (google images) its hard to tell.
Please can anyone confirm.
Ta.

its not double skimmed but probably is overlapped

Where the footwell joins the bulkhead it is overlapped as said above. And just below that you hit the double skin of the footwell.

As shown here:

Thanks guys, much appreciated