Help With Burma 1937 Watermark

Hi. I bought a stock card with some of the 1937 overprints (KGVI issue but with KGV portrait!).

There were two half-anna greens, one laid upside down. When I tested the watermark, it looks like the stars are inverted (ie, the central point is vertically down instead of vertically up).

My catalogue doesn't detail watermarks, but some Googling suggests this may be SG02w, which I notice one dealer estimates at £80-£90, which obviously makes me think I should keep hold of it!

Any Burma experts able to confirm if it really is such a thing? Obviously, you can't see the watermark, but as I said, the stars are upside down as compared to the other example.

Thanks.

This is not SG O2w, which also has a 'SERVICE' overprint.

If the watermark is indeed inverted, it would be SG 2w, catalogued at £3.25 used in the 2018 catalogue.

Hi. Thanks for the info, Peter.