I can't see why it wouldn't be. Save As basically creates a brand new save.
The one thing you need to be cautious of: when you're saving via Save As, you're brought into the screen where you see all your previous saves. There IS the possibility of overwriting a previous one if you click on any of them by accident, or trying to figure out the name of one. Just type in a name for the save (for easier finding) and then click on the Save icon.
If you happen to hit Save and overwrite something previous, you can restore a previous version of that save (icon to the left of the play button will bring up previous versions of that save file).
I've used Save As ... well, maybe a little too much, when I thought i might go back to certain points in my main save. I still have them backed up and only recently cleared most of them out of the actual folder (30+ save spots is a little too much lol)