Go ahead and use them. It 'should' be fine.
Don't over torque them, and don't crossthread.
I've had my motor hung by 1 bolt on that side; it lasted a few months; then after a drag race it finally snapped.
They're some pretty tough bolts.
[I crossthreaded mine... the most important thing I can think is to try to keep from putting pressure on the bolts as long as possible. jack the motor up to meet the mount, don't just tighten the bolts to bring the motor up.]
But yeah, I wouldn't buy new bolts to change mine again. That doesn't mean it's right or that it's sanctioned by vw. It just means that when I do another timing belt, I'm not going to buy those bolts. From my experience, they're pretty tough.