Welcome! (lurker since 2011)
That's an amazing find with so many original elements still intact. Congrats!
I know you prefer the look of flares on all 4 wheels, and I do as well for a lifted, modified Bronco. But as it currently sits, it's a prime example of a period correct Bronco from the late 70's & early 80's. It's not 100% stock because the original owner added a few pieces to make it their own, like almost every Bronco owner did before they became classics. Having just rear fender flares (and in white) was a very, very common first modification. Same with the bolted together roll bar, trailer hitch and left rear antenna mount. No, it's not in "just rolled off the assembly line" condition, but it's an amazing time capsule of how these Broncos were driven and enjoyed back in the day.
Personally I would leave it as is with just the rear fiberglass flares (maybe replacing them since one is broken). The rear fenders have already been cut, and you're not going to graft on original rear fenders since you want to keep the original paint (which I agree with). So it is what it is.I’m already torn on only having the flares on the rear, I like it much better when they have flares front and rear but wasn’t aware the front required cutting the front fenders to mount them.
I know you prefer the look of flares on all 4 wheels, and I do as well for a lifted, modified Bronco. But as it currently sits, it's a prime example of a period correct Bronco from the late 70's & early 80's. It's not 100% stock because the original owner added a few pieces to make it their own, like almost every Bronco owner did before they became classics. Having just rear fender flares (and in white) was a very, very common first modification. Same with the bolted together roll bar, trailer hitch and left rear antenna mount. No, it's not in "just rolled off the assembly line" condition, but it's an amazing time capsule of how these Broncos were driven and enjoyed back in the day.