No, it isn't reversible.
By hogging out the airway to fit a "connector tube", you made it necessary to shorten the remaining stem even further---remove the length of the reamed portion---to do what should have been done in the first place.
The proper fix when you received the pipe was to re-cut, re-funnel, and re-bend the end of the stem. Cut an entirely new button, in other words, and work back from it. Properly done it would have been invisible.
Those things could still be done but would now require dramatically more effort because of the stem's full length taper, PLUS you're now into full-diameter airway and past the original funnel neck. Now, Its thickness would have to be reduced overall for a considerable distance toward the bowl (probably about halfway to it) to gracefully arrive at the correct thickness at the button end---maintain the stem's lines---AND the height of the airway would have to be reduced by squeezing + heat, which will distort the lines even further, requiring still MORE cutting.
Since the feature that makes the pipe so rare and remarkable is the surreal stem length---only a very few of these pipes were ever made and fewer still have survived---shortening it more than necessary as a by-product of a hatchet-job fix shows a profound lack of understanding of what you were even working with.
Your push-back and the satisfaction you describe with the outcome of your "repair" after (presumably) considering what I said in my last post makes the situation even more distressing, because it makes clear you intend to keep doing stuff like this.
You are in over your head, sir.
I repeat: Work on pipes all you want, but please leave the historical pieces alone until you have gained sufficient knowledge and skill to avoid butchering them.
