@Ishni: Yes, it is possible. The only difference is that it's IVs/nature/shiny status is determined once you finish talking to Steven (you walk out of the pokemon fan club and he'll walk up to you). You will need to use Method 1 on the RNG Reporter instead of Method K for abusing roamers, so make sure you know your target frame.
Oh, and if you already released it by accident, you can kill it and re-release it by defeating the E4. Just note that you will have to abuse it before you face Lance. Iirc, there is a guide for it on the first page of this thread.
Oh, and if you already released it by accident, you can kill it and re-release it by defeating the E4. Just note that you will have to abuse it before you face Lance. Iirc, there is a guide for it on the first page of this thread.