1930s weights often are a little flatter in profile
True, but often they are very varied in profile, too. From my own examples of flatter profile weights, it is a more obvious feature in weights less than 7cm diameter.
My view is that the eBay example could well be 1930s, but might also be 40s or 50s. A mottled orange ground seems to have been used by Paul in all of those periods, but in weights with very clear domes (which I believe to be late 40s, 50s or very early 60s [apart from those with no obvious tint but which show apparent features of being 30s work!!]) the mottled orange that I have seen has been brighter (i.e. more yellowish).
Those particular blue/yellow canes are often seen in PY weights which do tie in with pre-war features. But, of course, they can also be found in later work, too.
It's all really so simple, isn't it?

Maybe I should buy this one just to check it out under UV? But I seem to recall that I have said before that I have not yet been able to cofirm other people's thoughts that UV results of 30s work is a brighter green than post-war work.
Maybe I should just buy 'cause I like it?