You hit the barriers and they moved 15 to 20 feet ( that’s a good impact )
I have kissed/brushed barriers in the past and bent a bunch of crap
If you said that the king pin bolts are good, and it was already doing this with the old king pins, but you only replaced them to be safe, then there’s no need to check for over tightened king pin nuts ( although I would ) It’s always a good idea to loosen up king pin bolts and re tighten them again, but very important not to over tighten or else you’ll choke it and will make it hard to steer, plus will develop premature wear of spindle bearings.
Also another thing to consider, when you set it down on the ground and trying to steer, now you are pushing and pulling on whatever cracks or bends there could be on the frame, think of it as the wheels are trying to separate from side to side as you try to steer. So if you have that much confidence in what you see to the naked eye, and people’s advise may not be good enough to what already looks obvious to you, then it may be a good time to send it in to a shop and let the professionals deal with it.
Here in Central Cali, and Southern Cali we have plenty of people who can do frame work, not to mention, they do bring their awesome set up to every race.