Being Captain Obvious here:
With the rust spots on the crank wheels, and the visible section of the bearing outer, it pretty much is certain rust was / is on the bearing surfaces, and / or the big end pin, big end ID.
An engine sitting around, can rust internally, as seen there. The area it's in, even just medium humidity levels, will allow rust to generate. Many / most synthetic oils are hygroscopic - attracting water, and even Castor oil will slough off surfaces. Bare metal, just loves to rust.
It's certainly a Bummer for you.
Make sure you get a recent stock Wiseco Crank, if you go that way, They had many problems with their Chinese sourced (I think) cranks, a while back. Predominantly 4t ones, but I did hear of a few 2t crank problems.
