Not really! Here's why:
1) c'è means there is. The original sentence didn't feature this structure. The semantic difference here is the same as in English.
2) Biscotti means biscuits, i.e. it is the plural form.
Hence, the most proper translation here is "Forse è un biscotto al cioccolato''. It's like replying to someone asking you what kind of biscuit you are eating, and you are not sure.