Message #1 Posted by Bo Kristoffersen on 11 May 2001, 12:32 p.m.
The HP-21 was introduced with an "old style" serial number add-on tag of 1504, however, a little later, e.g. 1512, it had a "new style" stamped-in serial number.
A number of models were produced before and after this "switch" periode, e.g. HP-55, 65 and 80, therefore my question: Which models, in addition to the HP-21, were produced with both styles of serial numbers?
Also, I have an early-version HP-38C manufactured approximately 6 months later than my late-version HP-38C (i.e. the lightweight version with the crisp keys), both from Singapore - was this common for the 30-series?
I am sure you collectors out there with gigantic collections can check this out easily.