Here in Oz, I would think that repair job would go close to the same cost as a new replacement bumper. I know what I would rather have on my ride if I was keeping it. Don't know that I'd feel right selling it without disclosing that it had a patch and paint done.
Current Mistress: 2014 F10 535D M Sport - Alpine White
Retired but not forgotten: 2011 F10 535i - Titan Silver; E53 X5 4.4L Sport - Space Grey;
E46 M3 Individual Convertible - Phoenix Yellow; E39 528 - Glacier Green;
E36 328 Convertible - Montreal Blue