You don't need to . . but it's a lot of clutter. I'd personally recommend doing this as follows:
- Back up the files you want to keep from your HDD
- Shut down
- Disconnect the HDD
- Install the SSD
- Boot up, and install Windows
- Let it do all the updates, and then shut down
- Reconnect the HDD
- Delete all the partitions on the HDD*, and create one large partition that spans the whole HDD
- Copy all the files you backed up in step 1 over to the HDD
* it's possible that Windows Disk Management won't let you delete all the partitions on the HDD - it might try to hold on to one of its small housekeeping partitions from when you were running the OS off of the HDD, so it's possible that you'll need a 3rd party...