So that's about the most brief summary I can show of the Malerne progression, one of the earliest next to one of the latest. There is however no middle link there, no example that is pre-war but substantially later than the Lebret / Malerne. I have my suspicions that some future find will reveal an original early Malerne Standard, and I think it will be a more finely finished instrument than the 1950s examples.
One of the 1950s Standards I acquired came with a mis-matched barrel that was the wrong length and a poor fit. So I kept my eye out for wandering Malerne barrels and a while later, one popped up for $10 and I snagged it. I was quite surprised by this barrel, which while it had the same marks as the other two Malerne Standard barrels, looked nothing like them. It was the same length, 63.5mm, but the shape of the barrel itself was more a uniform bulb rather than the more pear-like shape of the other two. The barrel rings were different also, strongly contoured to match the rounded shape of the barrel and wider top to bottom than the others, and also silver plated. This barrel obviously did not come from a 1950s student Malerne Standard. The finish is very highly polished, like the Lebret / Malerne. When I put it with the 1950s Standard, it looked out of place. It fit like it should and probably was fine functionally, but even though it had the right markings it was very obviously a substitute. So I kept looking for a matching barrel and finally two new-old-stock generic Malerne barrels showed up and those have no model designation, but otherwise are identical to the 1950s Malerne Standard barrels.
What we need to fill in the blank is a clarinet that matches this odd Malerne Standard barrel in finishing details. If it had silver plated barrel rings, it was probably silver plated on all the metal work. If the barrel was polished to a high gloss, most likely the rest of the clarinet was also. This was a Standard closer to the standard of quality of the earlier Lebret / Malerne.
The name "Standard" as applied to musical instruments has historically changed somewhat. For instance a Gibson SG Standard guitar is the fancy model with nickel covered double coils, ebony fretboard with binding, pearl trapezoids, transparent maroon gloss finish, etc. The SG Deluxe and Special are lesser models. I'm going to guess that the pre-war Malerne Standard was a professional quality clarinet.
The first is a photo of a 1950s Malerne Standard barrel and one of the NOS Malerne barrels. These are interchangeable differing only in the missing model designation. The second photo is the mystery Standard barrel. I'd really like to see the clarinet that one came from, or another one like it.