MA requires front plates if you have new ones. I have my original plate from when I first registered my old '62 Rambler still, they don't require fronts with the old "green number" plates. You can barely read the plate now due to all the fading, but I've never had a problem re: that.
Sadly, I wanted a vanity plate for the Boxster and that meant a new one... so I'm stuck with a front plate.
The other thing that bugs me about this is they charge extra for the vanity plate, not only at the ordering stage, but
every year at renewal. It doesn't cost any more now for the "unique" characters to be printed on my registration form, etc. but the state will take their fees any way they can. :ah: