Well, I can say it is possible, I'm just not into gut-wrenching surgery by removing all the parts then reinstalling the MOS ones to replace ALL the ones once worked for Bipolar and have to use new pots and their values and same profile install with these new parts - gets' a little rarer each time...and more hairy.
Once you do it, you realize that it's time intensive - each one afterwards just makes you want to simply keep the Bi-polar approach for the effort going into the conversion - you get less out of it each time - just in the effort.
Now, if you are doing it so SAVE your own equipment - then the one-shot to make it work necessity - is more of a labor of love, not in works - just in saving the nostalgia.
Now call me sentimental - if you wish, BUT this isn't for the Original Poster (OP), this is for those that think upgrading means more power. Think of it this way...Did you buy that radio for performance or for power motor mauling?
That's the crux of my view - do not buy a radio to modify to get more power out of it and make it do things it was not sold as intended - you can buy radios now that can suit your every desire - you'd be far better off owning and using those to pummel the listeners ears than to try and rework radio sections of equipment that was not designed for high-power applications.
A little goes a long way.