Brüko Type#4

When I got this Ukulele I didn't know who the maker was or the age, just that it was old and probably European. The only mark is a fairly unreadable stamp inside the sound hole that probably starts "Made in" but the location is now a smudge. It also has a very distinctive one piece wooden Bridge and a rounded "pressed arch" back. I have since found that the bridge and rounded back are classic features of the Brüko range so I asked the people a Brüko and they confirmed it is an old Type#4 that went out of production some years ago. They also told me it was made of "Aldur and Gabon"? Now I believe Aldur translates to Alder, (not a usual wood for Ukuleles?), or possibly Birch? but I'm stuck on Gabon apart from the African Country? If I had to pick a second wood I would have said Maple but I can't get Gabon from Maple no matter how I try (I have just been informed that Gabon Wood is a common name in Europe for Okoume and that makes a lot more sense, especially looking at the grain on the sides - thanks Graham)

The age is harder to be exact on but I've seen a 1970's Bruko Type#6 and its only mark was a similar stamp in the sound hole, but it clearly said "Made in West Germany". My smudge, (which doesn't photograph well), is too short to be West Germany and the Ukulele certainly pre-dates reunification, (if nothing else the old slot headed screws in the tuners confirm this), so...

Brüko started making Ukuleles in the early 1930's and anything pre-war would just have "Made in Germany" as the stamp, (the smudge is about the right size for Germany but more likely it would have just had Foreign or, but less likely Germany with no Made in"first during this period)? However I have never seen a pre war Brüko Ukulele so I can't be sure the things like the bridge design were the same then. I have seen one they made for a Swiss distributor in the late 1940's and 50's though that had a very similar sunburst finish to the one that features on the back of mine?

It also came with a very interesting wooden case with a sliding top and some other old bits including a very old feltrum and the cover of a learn to play the ukulele book printed in 1928, (not that this means much for dating though). Brüko say this is not an original case so where this came from I have no idea?

I should say that it sounds lovely though, still perfectly playable though the action is a little high for my taste and the marks that look like cracks are all just superficial on the surface.