It’s true. There are numerous cases in which automotive remote transmitters that look nothing like each other can be used with the same keyless entry system. Two keyfobs could have different case shapes, button configurations, brand names and even FCC IDs and still work interchangeably.
One fairly common example is the square Ford remote transmitter bearing our part number 211-1211, which is electronically equivalent to the peanut-shaped Lincoln remote part 581-1581, even though they have different manufacturers, FCC IDs, shape and so forth. Remote 211-1211 has FCC ID CWTWB1U343 and key fob 581-1581 has FCC ID LHJ002. See the two parts at the following link:
Ford-Lincoln Compatible Remote Key Fobs
Another example is an oval Nissan remote transmitter that is compatible with (and superseded by) a rectangular keyfob. One has FCC ID KBRASTU10 and the other could have FCC ID KBRASTU15 or could be made by a different manufacturer and have FCC ID CWTWB1U733. See these two parts at this link:
Nissan Compatible Key Fob Remotes
When it comes to aftermarket alarm system remote transmitters, this situation is even more common. In fact, there are Audiovox remotes that work for Code Alarm systems, DEI keyfobs that work for Ungo systems, and so on. So, like books, never judge remotes by their cover.