[ChristianK]

I had that thought, too. But even if those Yak's did resemble the P-51 in their outer appearance,the NMF finish of the latter would have been quite a distinctive feature for Geistenhoevel to distinguish them from soviet airplanes (I've heard from coevals that they saw the reflections from american planes even from the ground).
I know that meeting soviet planes in the Berlin area in April 1945 was much more likely than a dogfight with american fighters (even regarding statements of a german pilot quoted in Jet&Prop magazine a few years ago, that the acitivity of the VVS was remarkably low in the last weeks of war) but could have Geistenhoevel been that wrong?

P.S. Which source could reveal soviet loss lists in 1945 anyway?