No, the is no longer a factory rework proof mark.
The 8 3/8" early "S" prefix M29-2 shown below was a factory refinish after a new cylinder was fitted to replace one with a bulge and the barrel set back a turn. It was uniformly excellent. I did have to wait for a while for it to be completed however because, according to Vito in the Performance Center, the polisher who needed work on it before the refinish was out with a heart attack. He stated that the people who still had the level of skill necessary to perform that level of finish were becoming few and far between in Springfield. It was beautiful when finished, however.
Bruce