RevM  2.6 83/09/19 Rev M Sun-2/120 Sun-2/170 Sun-2 keyboard
RevNK 2.7 84/02/06 Rev N Sun-1/100U Sun-1/150U Two-tone keyboard
RevN2 2.7 84/02/06 Rev N Sun-2/120 Sun-2/170 Sun-2 keyboard
RevNV 2.7 84/02/06 Rev N Sun-1/100U Sun-1/150U VT100 keyboard
RevR  2.8 85/02/19 Rev R Sun-2/120 Sun-2/170 Sun-2 keyboard

Rev1.0f 87/12/29 Sun-2/160 or Sun-2/130, Sun-2 keyboard Sun-2/50 Sun-2/120 or Sun-2/170, Sun-2 keyboard 

520-XXXX/X-0X Revision N VT100
520-XXXX/X-0X Revision N
520-1101/2-03 Revision R

520-1103/4-02 Revision Q

Strangely the 520-1102-XX is the low (even) ROM 520-1101-XX is the high (odd) ROM