They can fit pretty closely to the housing, so it may just be that. Can you push it back in and maybe spray it with WD40 or something. You could then try to pop it back out and grab it with some pliers padded with cardboard or folded up paper towels.
The lifters should be stored submerged in oil and they should be smooth and flat on the face that runs on the cam. The button inside should be firm. If not, soak for awhile in oil with the oil feed hole facing up and pump it while in the oil to try to release the bubbles. See this for a more detailed breakdown.
http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/561128-waking-up-dead-lifter-prior-installation.html
If you do determine you need to get another cam, make sure you get the right one. The later ones have a slightly better exhaust profile and is an upgrade that can be made to an early engine. If you have a late cam already, make sure you replace it with one.
