while swapping a cam into my 318, my dad and i found pic related. also 360 was written above the cam timing gear.. is this factory?

 

I'm going to say "no". Are you sure you have a 318 and not a 360?

 

The Photo is just showing
1. The shop that did the rebuild.....
2. That the block is bored 0.030 over...
3. I think will be the invoice / work order or date the work was done.

Look to see if the cubic inches are casted into the block side...