[S Sheflin]

Greetings,
Hopefully, someone can help me.
I have documented several examples of Kl 35’s with consecutive Stammkennzeichen (confirmed by photos) that are apparently different versions; i.e. Kl 35 B or Kl 35 D. One features the single-strut landing gear leg of the “B” version, white the other has the multi-tube struts of the “D.”
Were Kl 35’s upgraded from one version to another during repair, or am I seeing a production line change?
Happy New Year,
Steve Sheflin