Hi Kenny,
I believe that 7503C2 is B738 9M-LNQ recoded. It left Boeing on delivery with a hex code which duplicated one of the Firefly ATR's and I think they have noticed it and recoded accordingly. It is in todays d/b update as such.
N704JA is a Cessna 172S Skyhawk SP c/n 172S10289 which is now HS-***
Thanks again
Alan