Mate grab a skyland rep that someone is selling cheaply and either use the 7750 from that or just buy it for the date wheel as this Navi needs a proper date wheel in it.
The original case of this model is polished just like it is now it was only the serie special that was brushed (Brushed would have been correct had the dial not been changed out).
Also I think the Navitimer old which this dial came from has black hands and a different chrono hand...I don't think it had the B on it but do a google for images.
Also do some searches on here as I did one of these ages ago and there should be some info from then..
Good Luck..