Ya you need a wide frame face to get an almost dead match. The very top flats are the same width. That is the reason I couldn't pick just any K frame. With a nickle barrel your pretty stuck with the barrel's factory profile. You can touch up small spots of nickle, Small small, like the small cuts in the ejector rod channel Not mirror polish spot. The barrel shank wear it sticks in frame window also.
When I used the 4' blue Python barrel on a model 10 frame, I milled and fit a adj sight using the longest tang, it came to face of frame and met the top of Python barrel.The mill just grazed the top of the slightly rounded 10 frame. Then the upper corners of barrel did not meet the frame tight . Had to change the bevels somewhat on barrel and needed re blue to match the frame anyway
Ir will never be a true beauty. The frame isn't really up to the barrel looks wise. If I ever come across a decent deal on a nice frame I can move parts. I have the original 2" barrel I polished of the evidence marks. Didn't take much. A trip with a cylinder though the blast cabinet a salt bath, a little time and it is a bead blasted 2" model 15 with a ball detent. Oh yea and new frame. lug.