I am rebuilding my first motor, the unlucky lady is a Chevy 454 from the 70s. I have the large oval heads so it isn't too bad a purchase. After removing the oil pan it is obvious that someone has been into this engine before, I'm no master mechanic but the evidence is there. I have a number of questions and will probably mess up some vocabulary, but if anybody has a little knowledge to impart, in always listening.

Certain connecting rods are noticeably a different color, a more rusty patina than their brothers. Is this an indication that these got very hot at some point, possibly an indication of bad clearences or bearings?
I pulled one and the bearing looked pretty good, smooth and not really discolored.
The rods have been marked with a stamp, most are in the corresponding positions, however the number one cylinder is marked as number 2, and number two is marked as number 8. There is an additional number 8 at the other end of the motor. Were these likely salvaged from a donor motor? I was under the impression that they are absolutely not interchangeable. Could this be a reason that they overheated?

As I stated this is my first full build, I've been a shade tree mechanic for a number of years, mostly out of necessity(driving old junk cars) and I always enjoy it. I'm trying not to spend a fortune, but I also understand that good products, and good performance come with a price.

Looking forward to any responses.