Yes, this is right.
At least from FICO perspective (my work module) this is still true as a result of S4 straightforward Finance could be a large leap forward from SAP New G/L accounting. Therefore after they had designed the HANA coaching materials they merely assumed that the scholars (consultants) have some operating information on New G/L. Some areas (for example like removal of redundant recent tables and replacement with a central one) will not be a lot of clear to you if you don't recognize why those things were there in the first place. Those elements aren't well explained as a result of SAP assumes you have already got the information.
To cut short, it is fine if you directly start in S4 but it will surely help to have some knowledge in traditional SAP (new G/L or classic G/L).