There is no possibility for a TM to have infinite number of states; so the problem is a trivial one and for any trivial problem decidability is straightforward.
Now, even if the problem is whether a given TM is having $10$ states (or any constant), it becomes a non-trivial problem of Turing machines (not of recursively enumerable set and hence Rice's theorem is not applicable) but is still decidable. Because to decide this all we need to do is to decode the TM description and just count the number of states. This is similar to answering if a given $C$ program is having $100$ lines of code.