Nice piece you got there! It is indeed a "type B" pommel construction. The unit marking is a bavarian one, from the "Cheveaulegers" cavalry unit. 15,000 Gottscho SM bayonets in total were delivered to Bavaria, with the typical "c/W bavarian-style" acceptance stamp on the blade spine, whereas Gottscho SD bayets (delivered to Württemberg) have a "c/S" stamp. The "Cheveaulegers" cavalry was unit type only known in Bavaria.
So your stamp reads either "5th Cheveaulegers Regiment, 4th squadron, Weapon nr. 53" or "5th Cheveaulegers Regiment, Weapon nr. 453"; When the bavarian cavalry received these bayonets after March 1915, the unit stampings didn't follow the pre-war standardized rules any longer and unit armorers stamped whatever they wanted.
In the "Seitengewehr 1914" book by Jackson there are other Cheveaulegers unit markings on Gottscho SM bayonets listed, the prefix "B" denoting "Bayerisches/Bavarian":
B.3.Ch.R.
B.3.Ch.R. 3.20
3.Ch.1.170
B.8.Ch.R.
Interesting to see the armorer using only capital letters (maybe to save time?), but also seen on other bayonets with different unit markings, too.