HP 19C Spring loaded Thingy?

[rprosperi]

Well... I was wrong and I was wrong....

@Joe - That one I owned for a very brief time, and I clearly didn't get to know it very well. I stand corrected.

My units:

HP-19C: 1711A with hook
HP-10: 1804S without hook

So here's the units reported thus far:

HP-10:
1711S without
1712S without
1802S with hook
1804S without
1808S with

HP-19C:
1711A with
1712A without
1801A without
1801S without
1801S with
1802S without
1804S without
1805S with
1905S with
1905S with


I believe (always risky...) the 10 and 19C shared a common chassis, so it would make sense they both had the hook added at about the same time. The units listed above seem to show the addition took place in early 1978, except for my 19C. I don't think my unit is a frankencalc (e.g. with base from earlier unit) as the hook mounting seems to affect both case halves. Seems to be a confusing history!

Also, it appears possible that units with-hook, or indeed the HP-10 were not produced in USA. Let's find out...

Does anyone here have:

A 19C made in USA with the hook?

A 10 made in USA (please note with/without hook)?

(edited to add Panamatik's machines)