Don't be concerned
Don't be concerned, gamma. I think it is an '04 & '05 thing. I don't know that there were tire monitors before those model years. I think it was an upgrade the same year the 2.4 liter engine was used, along with the all-red taillight lenses.
In any case, if you are not seeing a low tire-pressure warning on your dash, you should be OK!
RAV on.