Well, I am no expert by any means, but from what little I know, if the data plate did not have any of the Radio codes (R11, R22, R35) then it didn't come with a radio. The other option was the Accessory Group A04 that included a radio, and of all the plates I have seen with A04, the R code also shows up. you have neither. My understanding is the data plate controls what steel panels/parts the chassis is built with. Each code that shows up specifies a particular body panel, (i.e. H51 would indicate a firewall panel with A/C mounting and placement holes; lack of H51 would be a standard firewall), C16 would indicate that center console brackets on the floor pan were installed; lack thereof would indicate no brackets and no console, etc.). So no R code would indicate to me no Radio was installed, and the appropriate panel without the needed holes for the antenna were used (fender and inner cowl support).
I have never seen an E-body radio delete panel, but if what you have has the Chrysler part number and logo, then I am sure it is worth its weight in gold!
Other than that, you have a very nice 383 4bbl automatic, Lemon Twist with black hood and side stripe, Black Leather Interior, with A/C, bucket seats, and overhead console (an SE exclusive) R/T-SE.