Yes, if you want to see if there's already a request look or search in game requests, you must search from inside it for it to work (same with rejected and complete).
Again go search somewhere like Anime-Sharing for DLSite games (and other Japanese ones) that can't be requested in game requests, use thet RJ code on the end of the DLSite pages url. Don't go asking for a game in several old and only just related threads.