Question for early Model 1890 collectors|Winchester .22 Rim Fire|Forum|Winchester Collector

I’m looking for some insight into the variation of the carriers in the first and early second model cartridge carriers. I have noticed on 3 of my rifles (two first models and a very early second) that the carrier top surfaced is notched instead of solid as it is on all my other 1890s. I have found no reference to this variation anywhere online or in any of the better known published references. Does anyone have any information about this type of carrier. My theory is it was designed to be able to better see a cartridge in the action to tell if it was empty or not. I also think these were prone to breakage, as one of mine is broken and another cracking.

But I do noticed many other rifles in the same production periods that will have a solid top carrier. Did Winchester supply these as a redesigned replacement part? Were different type carriers used and installed in original production? Perhaps other collectors can check their early rifles and we can get a survey of sorts started. I have notched carriers in serial numbers 3192, 13993 and 22964.