The main difference is the 452 barrel is screwed into the receiver like all centerfire rifle barrels and yours are held in place with a couple set screws.
This rifle has a Timney trigger in it.
The 457 American MSRP is $515.00
I'm not a potential buyer but I see acouple of things you could do to help your sale.
Identify the rings, they look like Burris Signature which most people will consider as added value.
Post the trigger pull rate.
Good luck.
