more model 99 E dating questions

well I always wanted one so my wife bought me a 99 E series A chambered in 243 for our anniversary. I cant see the stamping on the lever boss. the serial number is D725xxx the savage serial number lookup says its not a valid serial number. it has light colored wood with checkering on the bottom of the forearm and the pistol grip I believe the checkering is pressed not cut. the gun is rusty but i was able to clean it up. gave 300 for it. i heard the 243 is some what more rare than other calibers but i mainly want a shooter. can you answer what year it is. I think it may be late 60's maybe 66 or 67