I found this for you:
Posted By: Dean S <S181715@aol.com> (cache-ntc-ac07.proxy.aol.com)
Date: 4/24/04 14:43
Have one HK 91 for sale. Rifle is new and unfired since leaving the factory in December 1979. HK date coded(1979). HK import. Comes with two mags new in the wrappers that are date coded mo/yr to the gun, original test target, muzzle cap, manual, and warranty card, and sling, as well as original box. Pics on request. 2600.00 plus shipping to your ffl.
Let me know how it works out.