If the manual doesn't say anything, I'd probably email the company. If the air bags did not deploy & the actual seat was not in it, I don't think I'd replace it. (I was very lightly rear-ended when I was pregnant & had the base installed. I didn't replace the base.) There was no pressure on the base to cause a strain.
Personally, I'd probably toss the base and just buckle the infant seat into his car until I was ready to go to the convertibles. But a lot of depends on how often the car seat goes in and out of that car, how much damage was done to the various cars, if you were hoping to use that base for another kid, etc.. I wouldn't really want to pay for a $50 base in increased premiums for the next three years. But if there was a lot of damage and you'll have to file a claim anyway, then I'd look into whether or not it needed to be replaced.