IMO, and I tell this to all my elk clients, if you don't care about the book, then take him and let your taxidermist fix it like it WAS!
I'm not talking about "building" a rack, but just replacing what is obviously missing. Sure there may be some differences from side-to-side, but taking that bull is for your enjoyment and satisfaction, not anyone else, so if you like him, take 'em and be happy.
The bull I took last year with a muzzleloader here in AZ had 6 3/4 inches of broke off antler of his rack on the left side.
I'm having it fixed as he isn't going into any books, just on my wall as he is the last bull I'll ever take.
Oh, as he was, he wasn't too bad, he still grossed 378 2/8..
Don Martin
Arizona Wildlife Outfitters