Replaced the original 13545621 with the 13529378 last night (that does appear to have an older serial #) and I had headlights off and DRL's on the entire ride in this morning in the sun. Headlights were on in the garage as well as testing by putting hand over sensor. Also put flashlight on sensor and headlights went off. Form, fit, function seem to be the same, pin configuration matched, so this does seem to be a viable option.
Note, for the swap, I started with taking the dash panel off with some trim tools and some of the clips were really tight as I got closer to the windshield. Could envision something cracking or breaking a clip. I aborted that, put some painters tape on the dash right next to the sensor and pried it up with a small flat head screw driver. Popped up easily once I got under it and plenty of slack in the wiring to comfortably pull it out a bit to unclip the connector.
Original on the left, replacement on the right.