Vincenta Kohlerta Synovè
V. Kohlert's Sons
V. Kohlert's Söhne
... and, of course, variants without the umlauts or accents.

"1930 - 1934"
Right after the Modell 1929 and right before the model with the "VKS" keyguards.

(Pete) There are at least four versions of these horns: Popular, Star, Highclass, and Regent.
From my current reading, there may also be a "de Luxe" and "Excelsior."
I have really no way of telling these horns apart: let's call the "Popular" the horn without a D# trill.
Here's one that has it.
Let's call the "Highclass" the horn that has the additional pearls.
Oops. This Popular model has them.

(Helen) According to research materials gathered by Uwe Ladwig, the Popular, Star, and Unser feinstes ("Our Finest") Modell, were available in the 1930s for an additional cost as "Super-Variante" (super variants).
"Late 1934 - Early 1935"
(Pete) This is one of many times I've liked looking at Helen's pics: I find something I haven't seen before.

Literally right before the horns with the VKS keyguards is this model in a very, very small slice of time.
The main difference from earlier models: same-side bell keys.
This IS the horn that the Selmer Pennsylvania Special stencil is based off of.