No! Tri-stars are those 12(?)-pointed star-shaped fastener heads that are used all over the place. Drivers for them are easily available. Edit: sorry, trisquares, not Tristars, like me Sis used to fly in. Famous for falling-off-cargo-doors, as I recall...
The allen key will fit it both, but the spline bit only in the spline bolts, so after digging out the crap from the head, try the spline first if you still can't see. Knock them well in with a hammer to avoid rounding them off. If that doesn't work, loosen with mole grips before you wreck the bolt.
I hate allen bolts, it's the worst kind of bolt, usually takes just a bit less force to strip it than to loosen it, and VW loves them. I would sink the bolts in acid and laugh while they get eaten alive for revenge. The 12-point star key is great for loosening stripped allen heads. I just force hammer the star in real hard, works almost every time.
I managed to get one CV joint off before I realised it was the 12 point fixing not an Allen bolt. You need the 12 point thingy to do the clutch too so worth having around the place. one tip is to put a plastic bag and cable tie around the CV joint to keep the grease and everything nicely contained once they are disconnected. You will get well and truly messy taking them off.
I ended up welding hex bolts onto most of my Allen bolts as they were completely knackered. The heat helps a bit too
