no I rechecked that more than once its definitly a 4 and it all looks like factory to me. I'd post a pic but my phone cant focus behind the alternator.

 

I wonder if it's not a factory replacement or crate motor then,I'd still bet it's a truck motor which can be a good thing in some cases since they were sometimes 4 bolt main steel crank motors.

 

I have a buiild sheet coming I hope on it from socialmedia@gm.com maybe it will tell me something there? The vehicle vin and engine id aren't the same either so I'm thinking it must be a replacement too but the suffix T4W should come up somewhere??
In the end not a big deal if the engine is tired then it will get strocked out to 383 if the block is a 350.