RAD remotes "can they be swapped?"

I have been asked this question many times, "I have a RAD 1.0 and lost the remote, can I use another RAD 1.0 remote that is the same Frequency?"   The short answer is maybe.  In my testing only about 1 in 4 will work with random unpaired remotes and robots.  That is even when all the numbers are the same.  The remote must be the same model robot, a 1.0 for a 1.0 etc.  They will not work across models (the 3.0 and 4.0 have different functions so they would not interchange anyway).  The remote and robot comb must have the same frequency.  This will be either 27Mhz or 49Mhz.  On the robot, it will be on a sticker under the base between the tracks.  On the remote it will be on a sticker on the back of the remote.  These must be the same frequency or it will not work at all.  If these items match then you still got to test it and play the odds of 1 in 4.  Even when I have the proper model and frequency the pair most of the time will just buzz when you move a stick and not actully move a motor.  So its either a case where the remote and receiver pair are fine tuned to each other or just a difference in the circuits with different production runs.  When I tear down these and remove the receiver circuit I find the antenna wire must be the same color as the receiver circuit that it does work with.  So that explains that there is some difference in the circuits that make during a production run of the same model.   So the only way to know for sure is to test a remote and robot together otherwise you are just playing the odds.  

I see single lost RAD remotes sold on eBay all the time just listing the frequency and feel bad for people that purchase them thinking it will make them a functioning pair.  I think many people just buy them and if it does not work they just scratch it up to a bad robot and don't complain.  At one time I threw all my remotes in a box thinking I could sort them later by the frequency stickers.  Instead I must manually test each remote/robot pair before I can begin any project.  I am starting a database to document the circuit revision numbers for comparison of functioning matched pairs, but it would still always test the pair first. I will add to this post as if find a quicker way of knowing a remote/robot pair will work before testing.  I welcome input from others on this as well.
In the end, the remote must be the same model of robot, the same frequency as shown by its sticker and the receiver board must have the same color antenna wire (either red, black, or yellow) however you must also know what the original robots receiver wire color was for that remote.
Was this any help? Just understand when mix them up, and the numbers are the same, I get a 1 in 4 chance of finding a pair that works.