Asking $650 shipped US. Up for sale is a 1940s Omega 30T2 2292 which I believe has the lighter Aluminum case. It measures about 34mm in diameter. Unfortunately no military numbers on the back but the case is in pretty decent condition with no pitting. It does look like someone however tried to refinish the caseback long ago. It has the original steel blue hands and the dial has aged into an interesting gray color. Service history is unknown but it winds and runs ok. I would recommend a service for frequent usage.
Meanwhile in eBayland: http://www.ebay.co.uk/itm/BRITISH-M...054978?hash=item58d247fc02:g:JskAAOSwcdBWSGVxPurchases made through these links may earn this site a commission from the eBay Partner Network £30 cheaper... But then again, it looks crap. Another score for the OF sales forum GLWTS!
Some of these were sold to the public after the war, so that might be why there are no markings on the back. Looking at your piece, I agree that it is the aluminum case-hard to find in good condition. That dial is in good shape for a 70 year old watch! Mine says hello!!
Great question Adam; the back to mine is also steel, with the original case #2292 (picture from original seller)