What Bob, Antelope, and 64 said.. It might have a long throat, but in the 60's some had that done to their rifles so more powder could be used.. That was the beginning of the long range shooting that I remember..
If the barrel has been shot, as Bob and others pointed out the throat will look dark and rough.. My current 7mm Rem. Mag. is 1200 rounds old.. I have been shooting it off and on for 25 years.. It is still an excellent shooter... 700's permit long seating due the the length of the action.. If the throat is good, clean it and as everyone said shoot it..