Reports from Guderian's 4th Tank Division confirm this conjecture:
"Combat with Russian tanks using 8.8 cm AA guns and 10 cm guns is insufficient. Both guns are clumsy compared to tanks, and are usually detected, targeted, and destroyed before they can reach their positions. In only one engagement between Orel and Mtsensk, two 8.8 cm guns and one 10 cm gun, all heavy guns available for defense, were detected and destroyed. These guns are as big as a barn door, and present a very large and easy target"
A. Ulanov, D. Shein, First T-34s, p. 161
Edit: I found a better picture, but it's marked with a reflection instead of a watermark.