Nokia Lumia or any WPhone browser has desktop and mobile browsing mode, IEMobile sends different user agent. Desktop mode does not send Windows Phone X.Y model argument. Find Windows+ARM+Touch+WPDesktop tags and possibly screen size to guess wphone or tablet. Its a hack I know.
Lumia 920 WPhone 8, desktop mode
Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0; ARM; Touch; WPDesktop)
Lumia 920 WPhone 8
Mozilla/5.0 (compatible; MSIE 10.0; Windows Phone 8.0; Trident/6.0; IEMobile/10.0; ARM; Touch; NOKIA; Lumia 920)
Lumia 820 WPhone 8
Mozilla/5.0 (compatible; MSIE 10.0; Windows Phone 8.0; Trident/6.0; IEMobile/10.0; ARM; Touch; NOKIA; Lumia 820)
Lumia 630 WPhone 8
Mozilla/5.0 (Windows Phone 8.1; ARM; Trident/7.0; Touch; rv:11.0; IEMobile/11.0; NOKIA; id313-3) like Gecko
Lumia 630 WPhone 8, desktop mode
Mozilla/5.0 (Windows NT 6.2; ARM; Trident/7.0; Touch; rv:11.0; WPDesktop; NOKIA; id313-3) like Gecko
Lumia 800 WPhone 7.5
Mozilla/5.0 (compatible; MSIE 9.0; Windows Phone OS 7.5; Trident/5.0; IEMobile/9.0; NOKIA; Lumia 800)
Lumia 900
Mozilla/5.0 (compatible; MSIE 9.0; Windows Phone OS 7.5; Trident/5.0; IEMobile/9.0; NOKIA; Lumia 900)
WP7.5 IEMobile9 desktop mode
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; XBLWP7; ZuneWP7)