I have a pair of GT clipless MTB pedals (like SPDs), which are 8 years old. Will they take SPD cleats?

I've lost the shoes with the original cleats and can't find GT clipless pedals anywhere, so need to know if the normal Shimano SPD cleats will work. The pedals look like SPDs: double sided, adjustable tension, silver alloy colour (not painted) with plastic GT end-plug on outside end of spindle.