Fantastic hat, Matt. I had one of these as well; sold it off because it was too large for me."Echter Mayser" in black - size 59 (slightly smaller but fits perfectly) - possibly early/mid 50s (?)
almost unused/perfect condition - very soft and malleable felt - medium wide crown band (3 cm).
super wide (for my hats) brim binding (1,1 cm!) on top and bottom with triple stitching
open, almost straight crown at 14.5 cm; brim at a great 7.0 cm
offered as "Homburg" - for me "Camber style" - also good to wear brim down as "Fedora".
interesting "signage" and thus hat history - a lot of info is already here in the threat:
Maybe Steve can sort it out again though, in case I'm saying something wrong...
"Echter Mayser" - so Mayser Ulm - as manufacturer in the crown and on the sweat
sold at "Joh.(ann) Zehme" in Munich: famous hat shop - itself rich in tradition - closed in 2013
label inside reveals that it was / could be obtained through "Hut Seidl" - also Munich.
Anton Seidl (himself a manufacturer) was significantly involved in "Mayser" since 1914.
As early as 1912, Seidl had also bought out the hat store "Joh. Zehme" in Munich.
The last owner of "Zehme" was Michael Zechbauer, Great-grandson of Anton Seidl via his son-in-law Curt M. Zechbauer.
https://www.hutstuebele.com/Home-MAYSER-von-der-hutlosen-Gesellschaft-zur-wohl-beHueteten-Welt.html
https://www.tz.de/muenchen/stadt/zehme-fussgaengerzone-traditionshaus-schliesst-tz-2691756.html
https://www.abendzeitung-muenchen.de/muenchen/hutmacher-raus-prada-rein-art-169428
PS: This is the same model as a hat Fastuni sold some years ago:
"Echter Mayser" in olive - sold by "Joh. Zehme, Munich" too
Have a look at the label of that one: not "Hut Seidl" but "Joh. Zehme"
The model number ("Art. 56465") ist the same like mine: "56465"
Also the controlling number ("Ktr. 33427") is nearly the same: "34406"
This one was stamp dated "21. Dez. 1952" - mine probably similar
https://www.thefedoralounge.com/threads/german-austrian-hutmachers.32103/page-261#post-2139729
Compare also Steve's "Echter Mayser - Superbe" with a Seidl-label inside...
https://www.thefedoralounge.com/threads/german-austrian-hutmachers.32103/page-112#post-1553627