I've never noticed an original used block with no paint in the nooks & crannies, but it does appear to have yellow highlight paint over the date & casting number on the passenger side.

I see the orange paint in the top pad pic, but is it anywhere else?

No warranty tag rivet/hole/other evident.

Six pack pistons had valve reliefs - what's the cast number on those, maybe someone can ID them as high or low compression.