... here is a 1940 Brazilian advertisement for the Teddington. It has the case references for these models. If a watch is not one of the three listed, I'd be suspicious.
From the Omega Vintage Database description for Ref. 2271:
"The red star which is sometimes featured under the Omega logo identifies the watch as being equipped with the same type of calibre as the one which obtained the best results until that point at the 1940 Kew Teddington precision competition."
This movement could be original to the watch. The red star dial would not be marked as a chronometer, so at the very least the dial has been altered. However, the condition of this movement is so rough, my thought is that this example has been put together with parts of various watches.
I don't think the Teddington was made with the RG movement, since these were not introduced until 1943.
One thing I've learned with vintage Omega is never say never, or ever. Anything is possible.
Hope this helps,
gatorcpa