Exactly, and of course that is what I have been advising. If you have the Fixer plan, go wild. No reason not to craft a level 40 Fixer if you can just make another one any time you want.
But that is a very rare plan. So if you do not have the plan I advise to wait to finish the Sheepsquatch quest until you are level 50 so that weapon would remain top tier as long as you play
To achieve anything in this game you must be prepared to dabble in the boundary of disaster — Stirling Moss