You did not mention which processor you are upgrading to?
To be on safer side, confirm you motherboard PCB version is 1.02G or newer.
On the other hand flashing an ASUS board is hassle free, use EZ Flash2 and you have help of CrashFree3 BIOS if it fails.
So in case the PCB version supports the processor, then buy the one you want,
if it does not work, put old processor back and do the BIOS flash.
The latest BIOS version is "1801" and I do think there will be no more updates for that board.
I'd say flash the latest BIOS and be done with it.
It is not very likely you will find 100% reliable info of processor revision before buying,
unless you can look at the code on the box package before.