Been down this road with a sunset piece myself, and here's what I learned: on a short gradient like ten rows, a batch difference absolutely can show. Dye lots on purples and pinks are notoriously inconsistent beacuse those colors are the hardest to reproduce. Some batches come out cooler, some warmer, some more muted. Individually you'd barely notice two beads sitting side by side, but spread through a smooth fade your eye catches the drift even if you can't name what's wrong. Gradients are unforgiving that way. A solid color block hides alot, a fade hides nothing. First step though: check what you've still got. Two-year-old beads are probably fine if you have leftovers. Delicas and most glass seed beads don't fade or degrade sitting in a tube, so if you weighed out what you acutally used and you have decent quantities of each color left, the smart move is to buy what you're missing and work around what you have.
Second: order new stock of everythign you can still get, and be ready to swap. When the new pink shows up, put a few beads of the old and new on a thread and lay them along your finished cuff under daylight, not under a lamp. If the difference jumps out at you there, it'll jump out in the bracelet too. Honestly though, my advice is don't try to recreate it exactly. Redo the whole gradient with all new beads of every color in the sky, then adjust the fade until it looks good on its own. It won't be a twin of the first cuff, it'll be a sibling, and that's fine for a gift. Trying to splice old and new batches into one fade is the path to unpicking rows at midnight, ask me how I know. One last tip: buy double what you think you need. If she loves it and wants a matching pair someday, or a strand snaps, you'll thank yourself. And snap a photo of the tube labels or write them down this time.