2013- engine matching with car?

[Shiloh93]

I bought a car that I have no clue what has been done to it, has a bunch of mods, and I see nuts and bolts missing in some places, ex: the bell housing. Was wondering if they put a new engine in it or even a boss 302 engine because they tried to make this car a boss, boss stickers, boss wheels, boss intake manifold, even made a custom boss shifter knob. I know it’s far fetched that they put a boss engine in but now I’m trying to tune the car and the tuner cannot get the tune dialed in and was wondering if I’m telling them the wrong info

 

[Shiloh93]

How do I look up the engine serial number to see if it matches the car