Early/Late Model Zephyr 550 Cam Chain Tensioner Interchangeability

Please forgive me for not spending more time searching old forum posts for an answer to this, but there was 293 pages of results when I tried to look. Which of course means that this might be a well-trodden subject, but to the best of my recollection I've never seen this particular question come up.

I am considering swapping out the manual cam chain tensioner I have on my '90 Zephyr 550 for an OEM unit. Yes, I know they can be problematic, generally what I've heard is that "they work until they don't." My thinking is that if the previous one I had installed before I put the manual one in lasted the 30 or so years that it was good, than a brand new one ought to last that long as well. And I wouldn't have to worry about setting it manually, which on the 550 engine is a huge p.i.t.a. given how much space there is under the carbs. 

However when I looked up the part number, I found something I'd never noticed before.



There was apparently two different cam chain tensioners installed on the bike depending on the engine number. I assume this means earlier model production versus later. My question is two-fold, I'm wondering if anyone knows if the two are fully interchangeable, and if there's any improvements made to the later model version that makes it worth seeking out. My bike is an early one and came stock with the first version (part 12048-1066), which is still readily available from places like Webike, CSMNL, and MegaZip. But whether the second version is an improvement or not, it's largely unavailable with the part number (12048-1111) shown here. However MegaZip lists a replacement part, which is 12048-1150 and that one is available from the usual places. So I'm tempted to get that one, figuring mama Kaw may have heard our pleas and fixed a known issue with a nice reliable part. Before I drop the coin though, I thought I'd shoot this one at all you fine folks and see if anyone has ever been down this road. 

I would have thought (but I don’t know) that the likes of CMNSL would show it as a “supercession” to the later part if compatible??

They do actually:  www.cmsnl.com/kawasaki-zr550b1-1990-usa-...partslist/E1230.html
Well I mean they show it as the supersession for the later model part, but not the early model one. So it still begs the question of whether or not they are interchangeable. 

Regardless, the part has been superceded, and seemingly the only one you would get is 12048-1150.      Which is still available because apparently goes in some Kawasaki lawn mowers.

 I own a Zeph 750 and run a manual chain tensioner for completely opposite your reasons.   The factory was the cross wedge type, very bulky and was perfectly fine, no problems...    However the manual one makes valve jobs, or top end jobs, a breeze,...very easy to loose and tightening, and I can also work on the carburetor in bike, specially #3, w/out removing the tensioner.....I can change any part in carbs w/our removing them from bike... .........and hardly needs any adjustment, if ever...which is also a breeze. 

Removing or reinstalling the factory tension was rather awkward and slow going..