1974 Commando Alternator

I have a 1974 850 Mark IIA Commando that was manufactured in June of 1974. From my research I have learned that during 1974 the alternator rotors had been improved with the magnets welded to the center. Apparently the improved part numbers were either 54202275 or 54201143. These part numbers superseded the earlier rotor part number 54212006. The rotor on my motorcycle however is different than any of these. The rotor's faces on mine have been machined flat allowing Belleville washers to be placed on both side of the rotor. Instead of a part number stamped on the rotor, mine has a part number ink stamped on the backside which is 54201144 with a manufacturing date I recall of 4/74. Here is a picture of my rotor showing the one Belleville washer:



I actually like the way this rotor is mounted. I prefer it over the star washer that is commonly seen. What I am wondering is if this rotor has the new, improved welded magnets or if it is just a modified earlier rotor.

My thinking is that when the time comes, should I go ahead and have this rotor re-magnetized or replace it with a rotor that has the magnets welded?

I have checked my part number and received absolutely zero hits on a search. It could be that I read the number incorrectly as it is pretty well faded.

Thanks,
Pete

I'm not much help but I can tell you that my 75 is original to me and has #54201143 on it and is dated 75/09.
Hope this helps a little.
Jaydee

Googling Lucas rotor 54202275 gets 48 hits,
and the other number 55 hits.

Can't advise anything on the actual rotors though.
Later is always better ?
LAB (moderator) with his encyclopediac knowledge will probably know chapter and verse though....

According to the NOC Service Notes, the welded rotors were 54202275 and 54201143 as PeterJoe said, however, neither of those numbers show up in the '74 or '75 parts lists.

My MkIII's rotor is stamped 03/77, 54201143.

Thanks for the replies. I suppose the rotor that I have installed in my bike is somewhat unusual. I am sure that the rotor on my bike is original as well. As a matter of fact I remember seeing a rotor for sale on eBay that was listed for Norton Commando that was just like mine. It even had the Belleville washers included. So at least I am not the only one with this setup.

I find it interesting that the John Player Norton replica and the later Mark III's that use the RM23 (the high output) stator also use a different part number rotor than the RM21 lower output stators. Now it seems that all of these rotors are interchangeable so I am wondering what the difference is between the high output and lower output rotors. Are they dimensionally the same? Does one have more magnetism than the other? Things that make me go hmm...