Steve, There are several threads talking about that era of YH wheels. (I searched March YH). It seems there were NO march YH rims produced, and that the only two batches produced suitable were Jan. 26-29 and Feb. 26-28. I think I would consider if the build date and VIN put the car early or late 04C. If it were toward the first of 04C, I would think it would be a better chance of the car receiving Jan. rims. If there were time elapsed and toward the end, it would stand a better chance for Feb. YH rims. Jan. wheels would probably have been gone from the pile! I personally don't think there was a big window for a range, normally pretty close.
I have never seen or heard of an 05A with anything else than a 4-18 or 4-21 YH. Other build dates are different in their own right according to that pile of wheels in the bin.
My 2C,
Bryan