If your engine is a roller motor (has roller lifters) you can put the Crower cam in it -- however you'll have to do some other things as well.
You really need to know exactly what's in your car now and what kind of computer is working the efi. It is injected right? The computer is supposed to energize the injectors, the distributor is supposed the fire the plugs all with the same firing order as the cam that's in it. So, if you're certain it's got a non-HO firing order, then at the least you'll have to rewire the distributor. I suppose it's possible somebody changed it to the non HO firing order without altering the computer or the wiring on the injectors so they matched up with the non-ho firing order. Not sure how well one would run set up that way. If so, all you have to do is re-wire the distributor and you're good to go. However, if it's a non-HO with a non-HO computer, then you've got to either get an HO computer or re-wire the injectors so they too match the HO firing order.
I don't know any way to tell for sure if an engine is a roller motor or not other than to pull the lower intake and look. If you see the spyder and dogbonz, then you got a roller. Maybe someone else knows the rest. In any event, I wouldn't get the Crower until you know for sure unless you can return it.
How did you determine that it's got a non-HO firing order? And what is the firing order that's on it?