I can't remember the years that caught the 75B in trannsition, but did your older model B have CZ USA Kansas City stamped on the right side?
If it did, I suspect you've already noticed the only changes.
The polymer guide rod has proven very durable and functional. Traditionalists will replace it with steel, but other than adding weight to the front end, doesn't really improve anything.
The recoil spring is a sore spot for me, because a number of the round-wire "replacement" springs are longer (at various weights) than original and won't lay flat. They will buckle and rub the frame as the gun cycles. The short guide rods (poly or steel) allow that to happen. Function doesn't seem to be affected, and once they take a set they run smoothly.
The trigger is really very good, once some smoothing, polishing and notably the hammer geometry is improved. At one time I had mine down below 2# in SA and found it was too light for "me" to handle well. I increased the pull weight about another pound and it's really good at that weight for me.
I know you'll be much happier when yours comes home after being worked by CGW.
It's a good pistol. Enjoy it and let us know how it shoots for you.