It looks to me like the union jobs stay in WA and the new SC plant will go on as non union, just like the employees voted about a year ago and the NLRB suit will be dropped.
I don’t know what the wage scale in the SC Boeing plant is but the employees seemed happy to have voted non union.
The biggest different is WA Unions have a nasty record of going on strike every fours years. Boeing can't keep shutting down production for 60 days at a time. The last time it hurt the company in a major way.