Sd Kfz 251/1 Armament?

[SGTGunn]

Hi,

I noticed in my copy of Chamberlin & Doyles "Encylopedia of German Tanks of WW2 1939-45" that the Sd Kfz 251/1, and its radio carrier variants the 251/3, 251/5 and Pioneer variant the 251/8 are all listed as being armed with two MG 34 or 42. The book also lists the Sd Kfx 250/1 as having two MGs as well. This seems to jive with many of the photos I've seen of both vehicles. I'm curious as to why both vehicles only have 1 MG in SPWW2?

Thanks,

Adrian