Go for it is what I say, there are a couple of things that could have happened. They might not have checked their email (or it might have gone into a spam folder) yet or they might not be interested, if it's the second of the two another email is unlikely to change their mind and they will simply delete it if it is the first then what harm can it do.
In the past in a similar(ish) situation I opened the letter that I was not sure what the situation was and made it clear that the letter was simply to let the other person know what my feelings on the situation were.