Facebook News Likely More Sizzle than Steak: Pro

Facebook plans to lift the curtain on a mystery announcement on Tuesday, yet one analyst told CNBC the reality of the news may not live up to its advance buzz.

Analysts are eagerly awaiting the social network's big reveal,scheduled for 1 p.m EST. Speculation is rife that Facebook could mark its first foray into the smartphone market, or reveal its own search engine to challenge Google.

Dean Munster, Piper Jaffray's managing director, said investors might not want to get their hopes up over something that is likely to be changes to Facebook's user platform.

"The reality is we probably think the core of what's going to get announced today is just changes to the basic flow of Facebook," Munster said, which could include tighter integration with search platform Bing. "The reason why we're not convinced that's going to happen today is too many people talk. and nothing substantial has been leaked out of this."

The company's shares have surged over the last several weeks, and last week hit their highest levels since mid-July above $31. However, Munster said the social network's investors should prepare themselves for a letdown.

Facebook sign in Menlo Park, California.
Harriet Taylor | CNBC
Facebook sign in Menlo Park, California.

"Facebook is moving in the right direction, but [there] may be a little bit of disappointment based on the hype going into this, because it's probably more tweaks to the platform versus anything that's going to be new," said Munster, who maintains a $38 target on its stock price.

Munster still believes Facebook's best opportunities lie ahead of it, with the company finally reaping the rewards of a revamped mobile strategy that was once a burden.

Ahead of Facebook's earnings report next week, the analyst predicted its earnings from mobile will be about 25 percent of its total revenue this year. "It's seems like they're making a lot of traction," he said. (Read More: Where Facebook Is Looking to Grow: COO Sheryl Sandberg.)