In general, yes. Doing a prelim GS year will give you a tremendous amount of US clinical experience. You will need to repeat your PGY-1 in medicine.
This assumes that: 1) you do well; and 2) you have enough time in your prelim GS to interview in the next match. Neither is guaranteed.
This also assumes that you can get a prelim GS spot. SOAP is over, I expect most of them are gone.
In any case, you best chance will be at the IM program at the same institution where you are training. Build bridges, make sure they know you are interested. Try to get some IM experiences if possible.