Acquired a early 80's K-Frame w/round original wood. Most of the original factory varnish has worn away and it appears the grips have shrunk. I'm wondering if soaking them in boiled linseed oil would increase size? Is this even a good idea or should I draw another plan on my ACME chalkboard. Thanks

Even if they did "grow" slightly - they would shrink again in short order I am afraid.

I'd refinish them as close to original as possible and if the smaller profile bothers you there are still some really good ones left on ebay.

I’ve never seen Magna grips shrink over time on their original revolver.
Have you taken them off and see if there is serial number stamped in right panel?
I’d guess that they are replacement grips and not original to gun.
There is nothing you can do to stretch them and make them fit.
Look for another pair.