As far as I can tell, the B-2 is (and always has been) referred to (technically) as the B-2A.
There have been some modifications, such as the changing of the internals of the bomb bay to accommodate ‘bunker busters’, yet it is still called the B-2A.
The reference to the ‘new’ B-2A is made mainly in regards to it being ‘qualified’ with the new ‘modifications’.
When they make minor changes to the design, the block number changes. The current B-2 fleet is up to the Block 30 standard.