Chainsaw Repair

Just got a pre-facelift MS261 (2011 vintage) and prefer the look of the side chain/sprocket cover of the facelifted version they started fitting from around 2015?? onwards- part number 1140 640 1704. Does anyone know if they are directly interchangeable...or if not directly, will it fit if I also fit later spec parts as well as just the cover to allow it to fit? Mine is pre CM, so the adjustable carb set-up, and the facelift covers seems to be fitted to mainly the later CM spec models. However I have seen on youtube some MS261 which must be the non CM models as there are carb adjuster holes in the top cover fitted with the later chain/sprocket covers? Need some help on this please.

I am aware the inner plastic cover over the brake mechanism is different, but would the later cover fit if this were changed as well? it's not an expensive item. Unless they are saying the screw attachment points are all different? Is the main body from the earlier version to the later one different?

I have now found out the later chain cover for the MS261 does not fit the earlier version. The Stihl technical update bulletin explains. As well as other differences.

I have a saw that is setup the other way around . It is a 2019 MS 261 C-M with the earlier smooth sided cover . Not sure how that came about as it was like that when I purchased it and was new enough that the muffler had not started to turn from being run .

I never seen anyone go back to old. But seen folks switch old to new. So must be possible?