Stoeger imported the Darne guns from about 1960, and ended their run around 1973. The earlier imports tend to be finished better, but, I’ve never really seen one that has been poorly fitted. People love to talk about “hand finished” guns, ignorant of the fact that few are, but, a Darne actually was.
Stoeger typically imported them in bunches, and sold them off-the-rack, which was a poor business model for getting a Darne gun that fit an individual. A Darne stock cannot be bent. LOP can be increased with a pad, but, that is all you really have to work with. If at all possible, handle the gun before you buy it, or do insure there a three day return policy, something which seems to be getting harder to find these days. You may dry fire an assembled Darne (DO NOT dry fire a Darne with the barrels removed!) and I would suggest you do so, as if the pull weight is above your requirements, it is tough to find someone to work on them. As always, look for signs bubba has been at it. Goes for all used guns.

This is a later James Wayne gun, same gauge and grade as what you are looking at. I lifted the picture to show a fitting issue that I have seen more than once on later guns:

[Linked Image from i.ibb.co]

I owned a gun that was about 3 numbers off of this gun, and was likely imported the same day. Mine didn’t suffer the same sloppy fit of the trigger guard extension, but, had blander pallet grade wood, and similar engraving, not something that inspired thoughts of artistry. Both of these James Wayne guns were built when the company was under extreme financial duress, and, it showed in the final product. Even so, I used my R15 20 for two decades, with zero problems, and regret ever selling it. I shot it very well.

Good luck.

Best,
Ted