Greetings! Awesome car - congrats! ::thumb::
The Bosses came with chrome front bumpers, and the Mach 1s came with the 'urethane' front bumper, which is why yours looks a little like a Mach 1 with Boss 351 stickers. I have the opposite, my Mach 1 came with a urethane bumper, but my painter couldn't figure out the primer, so I went with a chrome bumper instead (I was getting too close to a specific car show I wanted to participate in, so I put it aside for the time being). I actually like the chrome bumper on mine, not because it makes it look more like a Boss 351, but because it goes well with the rest of the chrome on my car and the light pewter paint. I think the painted bumper looks sharp on yours - it fits really well and isn't distorted from age, as I've seen many become.
The Bosses also came with Corporate 'dog dish' with trim rings wheels as standard, but everybody seems to throw Magnum 500s on them as well, so it seems there are a lot more 'non-original' Boss 351s out there than one might imagine.
The Marti Report should be able to help you with the particulars, should you choose to restore it back to its original state... which again, is completely your choice - it's your car, after all. The big thing is to enjoy the car, since I'm sure it wasn't exactly cheap to purchase. If your form of enjoyment is to have a car you spent a LOT of money on and are afraid to drive it because of the risk at losing value, then that's what you do. But these cars were meant to be driven and enjoyed while doing so... so I say, good luck in getting it up and running, enjoy the Hell out of it, and keep us posted while doing so.
::thumb::