There is a new issue bayonet that is very much like the HK version ,it looks great and I belive it is made by colt but is not the best steel 440A.

BAYONETS EICKHORN®

The Eickhorn-Solingen® BAYONET The Eickhorn-Solingen® Bayonet System 2005 is in current production and in service with NATO armed forces. System 2005 is the latest generation of the Bayonet 2000 and is a result of close co-operation between Eickhorn-Solingen Limited® and NATO armed forces, the System is unique to Eickhorn-Solingen and permits rapid retro fitting to all NATO assault rifles.

Eickhorn-Solingen® blades and tangs are laser cut in one piece from high carbon steel, hardened and treated against corrosion to MIL and NATO standards for extreme operations.
The above is from Colt (Diemaco) Canadas site. They have a bunch of other knives for the military on the same page here:
http://www.coltcanada.com/edged-page.htm