IWC with Caliber signed : C.403-423 Who can tell me what caliber is it ?

Hi from France!
I just bought on Ebay a vintage IWC 14k gold with an IWC hand windind caliber signed "International Watch C°, C.403-423". I need someone to explain me what caliber is it ? Any info are welcome, please help me..???
PS: I can email you pic of the movement!

The IWC Cal.403 followed on to the Cal. 402 and about 25,800 units (all types - there was an H version too) were build from around 1970 through to 1974.

It was a Manual wind with sweep seconds hand.

Movement Details
10.5''', Dm= 23.4mm
H= 3.15mm
17 jewels
f = 19800 A/h
power reserve 41h

hope this helps.

Please post a picture of your movement (or email me and I can help do so) levi@iae.nl

Dear Mark
Thanks a lot for helping me ! This IWC isn't a C.403, as I sayd it is written on C.403-423 ! I just sent you 2 pictures on your email address...Waiting for your answer to help me understand what caliber is it..?
Huge thanks from France,
Olivier.