NOT a BOSS 3.
IF LSI has 4 main ICs and it has ERS, XDI, RCK it is a BOSS 4.
If LSI has 5 main ICs and it has a ERS< XDI, and RCK it is a BOSS 5.
IF LSI has 5 main ICs and it has NTP, ZDI, ZCK, and ERS, it is a BOSS 6.
Note that the BOSS level is determined by software burned onto the ERS but it typically has supporting board structure.
The above is for the US side of the pond.
George
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)