I track 69 LR and STL built cars. I have about 1,300 69 Lynch Road cars on file.
A picture of the fender tag would be nice to help answer your questions.
I have no Coronets on file with an SPD of 7/11. All my 7/11 cars are R* cars
Other than the mistake body numbers in the 457xxx 458xxx range the highest sequence numbers (Body in white numbers) are in the 3147** range.
The highest VINs I've seen are in the 3138** range and on R* cars.