Please Help with this model cal. 89

Hello Everyone!
As a fanatic of vintage Swiss watches I found myself with this big dilemma in the hope that someone could help me.
Yes, this is my first IWC and I would like to know if it is an original cal.89?
What do the numbers on the back case mean?
My greatest concern (hence the doubts) is the dial! there is no Swiss Made hallmark. Is it normal?
Any help is appreciated.
Thank you
Cal. 89? Original?
Numbers on the back case?
Movement serial number?
Cal. 89 movement?

Hello and welcome to the forum. It appears you have a nice original cal. 89 from 1951. The numbers on the case back are the serial number of the case, dating it to about 1953.
I cannot tell you if the dial is 100% original or if it has had any work done but do not be concerned with the lack of a "Swiss Made" on the dial as that is quite normal and did not become standard until much later.

A very nice example.

You might consider to send it to Schaffhausen for a spa service.

Thank you all for all your useful comments and help!