Yes! (Correct) pre-registration is everything. ("Correct" meaning: There's no point "pre-registering" if you fail to account for the number of tests you'll do -- but hopefully the fact that you have thought to pre-register at all is a strong indication that you should be performing such corrections.)

That said, I agree with the other poster here about how important this really is for startups. It's critical to know if the drug really improves lung function; it's probably not critical to know whether the accent colour on your landing page should be mauve or aqua blue.