Actually, to this date, I haven't seen a Lachmann with a Cavalry-style wappen.
Starting with Tony's (Kaiser Bunker) all the way to Ed's.
So they do seem to have always been issued with Infrantry-style adlers.
This puts me in the mind to keep an eye out for an M15 Kuerassier spike and base. I bought my M15 (a CE Junker) many years ago when I knew little of spiked helmets and it has a line infantry spike on it... probably not original to the helmet. [-( So, a way to improve an otherwise nice helmet.