Identifying a Superbird without a fender tag

first dead giveaway is that in 70 a roadrunner only had a 440 when it was a six pack so it would read RM23V0..... so if the car your looking is RM23U0 thats a 440 4 barrel and likely not a regular road runner ......if the car your looking at is a V-code or Hemi then it could be either one, then you look at the back window ...a superbird had the flush back window ....and it will have wing support structure in the trunk

and it goes without saying ...if its a 383 no chance its a superbird.... RM23N0 is a regular road runner