When Baldwin modernized their tooling, the only replacement dome covers available were the modernized ones. The Grande for a while would purchase replacement parts directly from Baldwin. Later replacements would come from retired or scrapped locomotives. Hence, the 223 has modern Baldwin domes despite having been delivered with Grant flanged domes, and the 278 still has older Baldwin flanged domes, while other C-16s had varying combinations of the two. Since the dome cover is purely aesthetic it really didn't depend on throttle, dome or boiler replacement at all.