The barrels are pinned to the receiver, not threaded, not a common practice on rifles chambered for center fire cartridges. That might cause issues when headspacing the replacement barrel.
I don't know about the bolt face. The bolt face on mine is flat. It was a 256 WM that was converted to 218 Bee via a recycled Winchester 43 barrel with the receiver threaded to the barrel specs.
The trigger is really heavy on mine and there doesn't seem to be a safe cure.
I have long thought Marlin would have sold a pile of them in .44 Magnum back when they were introduced.