Stihl is discontinuing wide tip bars in the US for liability reasons. Wider nose bar, more kickback. More kickback, more accidents. More accidents, more lawyers. More lawyers, more money. I think what is happening is that dealers are getting the narrow bar part numbers, regardless of what they look up for any length bar now. Stihl has also removed the bar guide from their newer catalogs.
Your dealer is not right about the 3003 000 8846 bar being wide nosed, or a new PN. That PN is for the 11 tooth nose sprocket 3/8 32 inch 0.050 bar which is the narrow one. That is from my 2008 catalog. What you want is a 3003 000 9646 which is a 3/8 32 inch 0.050 bar with a 13 tooth wide nose sprocket. But those are being discontinued by Stihl, and may not be available any more from Stihl USA. I would try to order one, and if you can get it get as many as you can. They are going bye bye.