Did Frodo and Gandalf actually meet before Bilbo and Frodo's party?

[The Might]

Yes, they very surely did, as this quote from the Thain's Book encyclopedia points out:

Bilbo and Frodo had a comfortable life at Bag End, a spacious Hobbit hole under the Hill in Hobbiton in the Westfarthing. Bilbo had once gone on an adventure and had returned with wealth and knowledge of the world outside the Shire. Frodo learned much from him about the peoples, legends, and languages of Middle-earth. Gandalf the Grey was a frequent visitor at Bag End, as were a number of Dwarves, and it was believed that Frodo would sometimes meet Elves in the woods of the Shire. For these reasons, Frodo was considered quite unusual for a Hobbit.

I'll also try to find a quote in the books that supports the quotation above.