Head on collisions can do more than bend the frame horns. The rails can get missaligned and cause crab crawling, all of the mentioned stress points at every crossmember can be weakened, rivets stretched, body mounts scrwed up. My dads truck ended up with cracked exhaust manifolds 10K after he got it back and had had front end issues like no other.
If those frame horns are bent and I am planning to put more stress on it by adding it to my fleet of trucks that are tagged for 36,500 GCVW then IF I buy it it will need to go to a proffesional straightening shop and be gone over with a fine tooth comb. All things I can and would do but not for a $3500 truck with possible engine trouble.
My 00 Dually was bought with a salvage title that had been totaled again but approved to be rebuilt. Had an engine fire but the chassis still only had 46K miles on it. None of the paint was damaged either. Needed an engine wiring harness and new engine. Basically I bought a good chassis. That ford might not have a good engine or chassis.
Hard for me to decide a value.