IWC Watch ID Help

I inherited a box of wristwatches (mostly ladies) and found a few cool ones. I would like help authenticating first and foremost, and then go from there. These watches are all from the mid to late 80s in the collection I received and have not been touched since. The watch has some scratches and light signs of use, cuir veritable pressed into the leather band. No iwc marking on clasp. I am unable to get the back removed to see movement. The watch is not currently running.

some more photos. sorry watch face appears blurry, looks sharper in person.

I don't recognize this as a genuine IWC DaVinci. I may be corrected, but I hope you did not pay too much for this fake.

Thanks for your replies, I did not pay anything, this watch was included in a collection by my mother that was recently passed to me. I do not know what she paid or the watch history etc. I am curious how to get the back off, does any one know if it pops off, screws off or if I need to undo those tiny flat head screws first. Thanks !!

If the screws are real, I'd try unscrewing them first.