Yes; the early ones had no O-rings, relying on a (very) tight fit to prevent leaks.  I've had to use multiple applications of the heat gun before the die surrenders.

I've been careful not to put excessive strain on that cast handle, to the point of taking the square frame off the machine, holding the base upside down in a padded vise and heating and gently but persistently tapping the return plunger at the bottom of the die with a plastic mallet.  I use a nut of sufficient size to cover the bottom of the die as a spacer.

It's all apart and old lube cleaned out 
Ready for new.