This is the only way that I've found to get you on Gingerbread, without having the option to OTA, without root, and without having an update.zip. I haven't seen an update.zip for 2.3 out in the wild for the Fascinate. So it looks like, if you want to go to Gingerbread, you'll have to follow these steps. This will completely wipe your data, so be warned.
To do this, you'll need Odin
What you'll want to do after snagging Odin is download this
file. It is the latest OTA for the Fascinate, stock and unrooted.
Oh, and make sure you have the correct drivers for your phone. If you're not sure, use this
Once you've got the correct drivers, here's what you'll want to do.
1) Power off your phone and pull the battery out. Leave it out
2) While pressing the Volume Down button, plug the phone into your computer. Keep holding that volume button until you see a yellow sign and the word "Downloading..."
3) Open up Odin. If everything is working right, you should see a yellow box that says COM and some number in it. If not, try a different cable or a different USB port on your computer. If it works, continue to step 4, if not, I don't know how to help you.
4) Click the PDA button and navigate to your CI500_VZW_EH03_GB_CM.tar.md5 file.
5) Once both files are in place, click Start.
It takes a while to work, but once it's done, it should reboot. Once it boots back up, you'll be on Gingerbread, completely wiped.