From what I've read, yes, you should keep trying.  I've managed to leave messages a couple of times, but have never had her call me back yet.  That doesn't stop me from trying every so often!

But if you're wondering whether you should disclose extras that you received but you don't think are on the menu...my take is that she has a great menu already. Enough for most guys to make a decision. If you mention something special that isn't normally available then you might set expectations for some guys that won't ever be met.  

Just my 02¢.