They were made here in Salt Lake City, in an Easton facility. I had one just like that but was more red, with cantilevers on the seatstay and lovely straight bladed tapered unicrown forks. The seatpost was seized something fierce and the fork was misaligned, so I cut it into smaller pieces and took it to the tip. Mine was built with Shimano Mountain LX components and Araya RM-20 rims, so probably 1990? Got it to strip the parts off of, and am still using the wheels on another old beater MTB. Cool frames, and I think the Grisley frames were made in the same facility.

Pic taken from Retrobike.co.uk