The main thing is that it is your choice and I believe everyone would respect that. Is it the norm for the tag to be blank? No, not based on many other examples. If you want to go against the norm, you'll just need to be prepared to provide information why.
Would also point out that if you got your car when it was 15 years old, that would be roughly 1983. MCA started in 1976 and there was quite a following by '83. There were lots of owners buying up obsolete parts and sourcing details. I wouldn't consider it unreasonable that the decal could have been replaced by the time you bought the car. I have seen a bunch of these decals in NOS condition, so I know they were available.