No company is going to answer "do you have product-market fit" with a "no". First, it's not like you hit some sort of binary inflection point where you don't have it then do. Second, even if indicators appear to point to some traction, it's a set of plateaus, some that may be permanent. If you don't know the internal details about expectations, funding, commitments, etc. you have no way if knowing that a 3-month upward trend is PMF. Finally, every company will frame their progress in the best light, even if that means subconscious outright lies.

I personally think you're better asking what are you trying to do, coming to your own conclusion as to if it's a real problem that you personally believe in, asking what they've accomplished and why THIS COMPANY is better positioned to succeed.