Yep. It is a little time consuming to machine / finish that octagon profile.
Since the top flat of the octagon has to be timed so it is perfectly parallel to the top of the frame, the barrel shank has to be trimmed for the cylinder gap .002", and to trap the extractor housing between the band and the frame. Then to draw-file the machining marks off the flats so you have sharp parallel points on the octagon and keep a sharp banded shoulder. This is all done without final tightening the barrel to the frame. Round barrels are so much easier because the timing issue is much less critical.
There is also the work on the extractor housing. The inside radius that hugs a round barrel has to be machined flat to hug the flat of the octagon. Since each caliber barrel may have different barrel diameters, the extractor housing not only has to fit inside the round hole at the front of the frame, but also fit flat / parallel to the flat of the barrel.