Default [Q] Is it possible to install a stock ROM if 4.3 and a locked bootloader is in place

Is it possible to install a stock ROM once 4.3 and a locked bootloader is in place. I've looked all over and I seem to read conflicting stories. So...

I have a Samsung S3 Telus (AT&T) version running the latest 4.3 as of May1st, my bootloader is locked and I have a tripped flash counter.

If someone actually posts a I747MVLUEND2 rooted image can I flash it?
Can I flash an older version I747MVLUEM series?

Oh yeah my phone is NOT rooted.