Whilst the odd flap tweak or a vortex generator here or there might be considered such an 'improvement', total design of the 7-late-7's centre wing box structure is in an entirely different league.
I don't think it's possible to do a "minor change" to the load-bearing box. If you change just one little thing, you've got to go back and do the FEA (Finite Element Analysis) again. So even if they just missed a single hole for the bolt for the clip to hold the strap that holds the name-tag on, it's a "major".
But, on the other hand, believe nothing of the press releases and the reason for the delay. They forgot the landing gear.
Re the Titanium bolts, if everyone is using them, I'd bet the kinks have been worked out. I don't recall seeing any "cadmium-plated" sockets in my A&P's toolbox. They are mostly Chrome plated from Craftsman or Proto. Did a quick google though, and you're right, between '42 and '45 the US military did produce a set of cad-plated aircraft tools at Wright-Pat. It might be more prevalent than I'm aware though.