"... However, why would I want to spend $1200-$1500 or more on a gun I bought used for $350? The only justification is to have something special that I would enjoy owning and shooting for a long time."

That's a perfectly good reason to do it.
People spend much more for much less in return. It isn't always about monetary return,,that's why they're called 'hobbys'.

That stock would make into a straight grip nicely from the looks of the toe line.