[Premium-Rx] AOR AR7030+ Questions

[Arthur Delibert]

Does anyone know:
 
1.   In what year AOR began to make the 7030+  receiver (as opposed to the plain 7030 (not +) receiver)?
 
2.  When they began to make the 7030+, did they just continue the serial numbering they had started with the 7030 (not +), or did they start the serial numbering all over again?
 
3.  If they continued the serial numbering that they started with the 7030, what was the serial number for the first "+" unit?
 
Many thanks.
 
Art Delibert
KB3FJO