Introduction of the Explorer II ref. 16570...when...R-series?

[Hªªgen]

Trying to figure out what "generation" my N-series Ex II actually is? Was R or L-series the first of the 16570?I can see that L-series is a s late as 1990 and E, X, O and N are all 1991 from the serial lists (making mine an ultimo 1991 production).

<a href="http://tinypic.com"><img src="http://i5.tinypic.com/20py59l.jpg" border="0" alt="Image and video hosting by TinyPic"></a>