Well, there were several lenghts.
There was the standard infantry weapon, with two models, the M41 (448 510 available in 07.1870) and the M62 (434 567 available in 07.1870).
In my main source the following ist given:
M41:
length 1420mm, barrel length 900mm, weight 4900g. Bajonet lenght 566mm.
Weapon wasn't browned, other parts are brass.
M62:
length 1360mm, barrel lenght 845mm, weight 4750g. Bajonet lenght 580mm.
Barrel is round and browned, other parts brass.
Then there were shortened variants for Pioniere (engineer) and Jäger (Chasseurs, light infantry).
The shortened variants had the system and maybe barrel shortened.
Zündnadelbüchse M54 for Jäger batallions:
length 1245mm, barrel length 785mm, weight 4500g
No numbers of use given.
Zündnadelbüchse M62:
length 1255mm, barrel length 785mm weight 4500g.
Sources are conflicting here, some say four prussian Jäger batallions were issued with them, others say there were just 200 for field testing.
Zündnadelbüchse M65 for prussian, hessian, saxon Jäger batallions:
lenght 1230mm, barrel lenght 770mm, weight 4550g. Bajonet/short sabre length 645mm, length of blade 497 mm.
Barrel was browned, other parts brass, no barrel rings.
Available in 07.1870: 29 896.
I omit the Pionier ones as I guess you want an infantryman or Jäger weapon.
Source:
Die leichten Waffen der deutschen Armeen 1841-1945
Ludwig Baer
Journal Verlag 1976
No ISBN
Let me know if you need more.
HTH,
Manfred