Go for it. I’m finding that the ones with a lever on the side are the simplest, mechanically. I found info and supplies at https://vintagepensacsandparts.com/ and Grandmia Pens on YouTube shows the innards of lots of models.
I finally figured out it was a bad stick of RAM in my server that has been causing random freezes and not some stupid mistake on my part. Thankfully it’s DDR3 so I can keep both of my kidneys and still afford the replacement.
I’m happy with my Amazafit balance and I can see the main screen stats without my glasses.