Cold spring day in the mountains so a wagon ho day in the shop.  

Sliding around underneath car noticed some rot at corners of centre floor brace close to frame on both sides.  

Near as I can tell this reinforces the floor at front of passenger footwell?

Hard to tell for sure because of 55 year old undercoating but appears to be bolt in part?

Is this piece available in reproduction?  Or is this something that I should worry about?

Will try to get photo tomorrow, car is up on jack stands so 

don't know if can focus camera that close.  Do not see any obvious welds but there are 2 large rubber body

mounts on either side next to the frame rails, and two large nuts on either side of tunnel hump. 

I think you will find those nuts are for the seat belt anchors.