It's reasonable to ask, because they can already tell that you have 6 years of general software experience. Maybe they need someone who has shipped products in

It's reasonable to ask, because they can already tell that you have 6 years of general software experience. Maybe they need someone who has shipped products in a particular framework. I'm sure you would agree that there is a difference between someone who has 6 months of experience doing something, versus 3 years and versus 10 years. Would you hire a musician who has 6 months of experience playing an instrument and just hope that they can learn enough to play professionally, on your dime? If they don't happen to pan out, it's the hiring manager's ass on the line (and in this case the entire company) Apply, hope for the best, and move on if it doesn't work out.