Terry -
I went through an upgrade a few years ago. I had a bunch of MT1 accessories that I wanted to use with the new MT2 lathe. My solution involved a number of pieces:
1. I bought an adapter that screwed onto the 1x8 thread of the new lathe, and that presented a 3/4x16 stud to receive threaded accessories. That was cheaper than buying a new bottle stopper mandrel.
2. I had an MT1 bottle stopper and an MT1 step center, and didn't want to replace both. So I bought an adapter that consisted of a male MT2 and female MT1. This allowed me to continue to use those two MT1 items. As others have said, if the the situation had been different and I hadn't wanted to address both of these MT1 items, it probably would have made more sense to just replace the taper fixing.
3. The most expensive MT1 item I had was a jacobs chuck. Fortunately, it had a removable double-ended arbor - MT1 at one end, and JT33 at the other end. I found a replacement MT2-JT33 arbor that was far less expensive than a new jacobs chuck.