I believe so. Your nomation should be something like XX### (i.e. MD612). First two letters are for you state, first two numbers defines senator or congressman. I don't know what the numbering convention is for a big state with more than 9 congressional district. For example, for Maryland, Senator Cardin is MD621 as he is the junior senator. The last number supposed to be the vacancy.
So if your senatorial nominations have different last digits, more than likely your senator is filling two vacancies this year.