Stock Exchange...
Jacobs Ranch--Re: Using a heavy-bbl stock for a light-bbl Rem 597: I don't foresee that you'd have any problem, except for a gaping amount of space between the bbl and the fore-end of the stock. If that wouldn't bother you, I'd say "go for it!"
On second thought, make sure that there IS support for the forward end of the receiver, in the new stock. Lacking that, you are in for a serious action-bedding session, not that that'd necessarily be a deal-killer, just more putzy work.
On third thought, why not get the right stock for the barrelled action that you have? Unless you got a screamin' deal on the heavy-bbl stock. Perhaps karma is trying to tell you that it's time to install a heavy bbl on your 597 action.
Perhaps it's time for me to quit considering, and re-considering...