The info on the wheels supplied by your well informed parts rep appears to be bogus. Just looked up the front wheel for both a 2015 and a 2016 SE Street Glide. 43300321 is the front wheel part number for both bikes. No difference in the front wheel itself. Why your parts guy couldn't have just looked up the part numbers for comparison is something I don't know either.
That the wheels are the same in no way suggests that just installing sensors will make TPMS work though. There are other parts somewhere on the 2016 that must read the data the wheel sensors transmit. Maybe just bluetooth in the radio or some dedicated receiver somewhere else. But there's got to be something else going on somewhere.
Part numbers for the radio are the same for both years. So (perhaps with a software patch?) the 2015 radio should be able to display whatever the 2016's radio can display for TPMS data. The fairing harness for both bikes has the same part number also. The main harness, however, has different part numbers for the two different bikes.
Looking at the schematic for the 2016 harness don't see anything on that main harness that is noted as being TPMS in any way. So no dedicated receiver I'm seeing on a quick look now. Perhaps the sensors are just bluetooth sensors and the radio just needs an update to handle them?
No idea if that's right or wrong. But it's not inconsistent with what you can see actually looking over the parts lists for the two different years bikes. The only thing really learned for sure, however, is that the wheel is the same on both year bikes.