Start buy asking the guy you bought it from - depends on how much of a mate he is...
If you don't belive him then pulling the head off is 1 way to check.
As for the car still working without the restrictors, yes it will, but depends on how much track stuff you'd be doing - if its just the occasional spirited drive the car should cope fine, it simply comes down to how much time you spend in the higher revs as thats when the oil battles to get back to the bottom end...
my 2 cents, im sure there will be several opinions...