The insulator nose/insulator tip (white ceramic) is not fouled. Which is what fouling is mainly. Still white or off white. Both electrodes are maintaining crisp shape. No burn away. You have no problem to solve. Running rich was your word. You have no symptoms while driving/idling.
As the Shakespeare play says: Much ado over dodo.

It would depend on how long the plugs have been in there/mileage. 5 weeks or 5 years as far as normal tune up. If you change to R45 watch for running hot on temp gauge. All the FLAPS say R43.

1954 factory spec for plug is:
"Thriftmaster AC, 44-5 com" *
"Loadmaster AC, 43-5 com" *

gap .035

* According to NGK, heat ranges are NOT universal between manufacturers.

Fuel has changed since 1954. Octane, leaded, unleaded, ethanol..........compression ratios....emissions...factory knowledge in 1954....Possible factors that caused a change in what heat range plug is best now-a-days. Mileage and performance is a good measure.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn