The New York Post says some Jewish Republicans seem to believe so:

Republican presidential candidate Mitt Romney is facing a new challenge: He's having trouble raising money from some Jewish donors who mistakenly believe one of his opponents, Michele Bachmann, is Jewish.
Some Jewish donors are telling fund-raisers for Romney, a Mormon, that while they like him, they'd rather open their wallets for the "Jewish candidate," who they don't realize is actually a Lutheran, The Post has learned.
"It's a real problem," one Romney fund-raiser said. "We're working very hard in the Jewish community because of Obama's Israel problem. This was surprising."

Wait. First, I thought pretty much the one thing people knew about Bachmann is that she's from the Christian right. But forget about that for a minute. Doesn't every American Jew know that -mann names are invariably non-Jewish?