I'd leave it as is, maybe a de rusting with wire wheel or fine flap wheel, just don't get carried away. Far more important is the rebound, IE ball bearing test, or is the face hard?
As for the rounded corners and such, my new high dollar Refflinghause anvil came with a perfectly flat face and edges that had a tiny 45 deg. bevel. Immediately I rounded the corners a bit with a flap wheel, after a while I rounded the edges more, more radius at the horn end, less toward the heel, will most likely leave as is now. I primarily use this anvil for blacksmithing though, and currently do detail work on a 4"x4" post anvil I made.
A blacksmith anvil is over kill and kinda less than ideal for blade smithing. The horn gets in the way for one thing, for another you don't use all those radiuses that a blacksmith uses for forming. If you get into blacksmithing you'll be happy to have the rolled edges.