Yes. there should be adjustment screws on your gun. Near the trigger. The sears will adjust how much you have to pull the trigger before it sets off. I'll go look for a diagram on that gun and get back to you. But yes, shorter (lighter) trigger pull is possible, i'm thinking. It looks like there is a two stage sear, but they work together as one. Weird... anyways, theres two screws to hold the trigger guard onto the gun. If you can see a third thats your adjustment screw. Just play around with it in small increments, i've never adjusted a gamo trigger. Then shoot. Be careful, if you slip the first stage and adjust too much the gun may go off faster than normal or by itself, so small increments. Also make sure, since it's a springer, to tighten down all the screws on the gun, maybe even loctite em. The tighter the better with a springer because it will rattle all the screws at some point and cause inaccuracy. Also, i believe that gun is a break barrel, make sure to keep the pivot tight, but not overtight. It most likely had synthetic seals so no lube is necessary but you may find it necessary to clean the barrel.
