Yep those tensioners are best to be replaced every time you do an engine build. Test yours by placing it into a vice and slowly closing the vice, it'll take some time to fully get the pin down and when you do, put a small screwdriver or allen key into the hole to hold the pin down. Then remove the tensioner from the vice. Now time to test it, quickly pull the screwdriver/allen key out and if the tensioner pin pops out immediately at quick speed then its working. If it doesnt pop out immediately then chuck it in the bin. I'm not sure if Meek sells ones to suit a GSR so it might be best to ask him.