Its definitely not a stock EM1 ECU because its much longer and rectangular.. Pictures of stock 00 EM1 look to be more squareish right? The ECU I currently have has no outside stickers and according to the owner its chipped... I dont exactly know what that does for me since the only actual performance mods are really just a mugen twin loop exhaust and AEM intake.

 

Remove the cover, take a picture of the inside of the ECU and post it up here. Also, the ECU identifying sticker on the side is duplicated on the top left corner of the grey female ECU plug receptacle. If it is there, you can identify it from there. If not... clear, close up pics will help us help you. Now, the info on the chip is a crap shoot... the only way to know you are safe is to dyno test the car and verify safe A/F's under wide open throttle operation. Or, you could trust the guy who sold it to you... your choice.

 

It's most likely an obd1 ecu p28 or p06 converted to vtec. If it is chipped with the right tune, it should be a problem, but without knowing if it's a good tune maybe buying a new chip wouldn't be a bad idea.