You can be shure that this was an Ju 88 P-1 with W-Nr. 1398.
See the attached pages of 2 FB's. One gives the aircraft as 1398 and the other as CI+WP and P-1. (1398 had the Stkz CI+WP
).
The document "Erprobungsträger PAK 40" from 22 April 1943 (source: BA/MA Freiburg RL 36/65) gives this Ju 88 with s/n
and Stkz as an (former) aircraft of the "Versuchskommando für Panzerbekämpfung". (Have no copy, only notes.)
The GQM entry for Ju 88 1398 from 1943 must be wrong. I think the entry from 1942 is right.
23.01.42, K.Fl.Gr.606, 40% (BA/MA Freiburg, RL 2 III/1179)
Regards
Peter