They might be ok but they're probably not.
I've thrown too many spindles of DVDRW's away to take a chance.
I just stick to my Datawrite Titaniums now, have never had a duff one in a long long time.
Whilst we're on the subject, beware the cheapo Philips DVDRW drive from SVP, I bought one and it was intermittent with burning. It got so bad I couldn't rely on it so I binned it. I could have rma'ed it but they probably would have tested it ok and for £20.00 it really was just too much messing about. Return postage would have cost a fiver as well.
You live and you learn.
I have a Pioneer 111 drive now. So far, it's been faultless.
In fact, thinking about it, Pioneer have been the only brand of optical drive that haven't failed on me. I've had Philips; Sony; Liteon; Samsung and NEC all go belly up on me.
Oops, I be rabbitting