There's an 8v 85 golf (hydro lifters) in the yard.. are the lifters the same?
I've always been told that lifters and cam lobes mate for life...
New lifters are only $10 ea...
cams and lifters get wear patterns on them. thats why you have to "break in a cam" when you install a fresh one in an engine. mechanical heads can use whatever cam/lifters you want, because the cam rides on the adjustment shim, so the lifter never even gets a wear pattern. then that kinda negates my previous statement, because when you adjust the valves on a VW, you essentially change half of the lifter. and the lifter is what has the wear pattern on it, but i guess a new lifter wouldnt have a wear pattern? so i guess it would work. but if you take one lifter out of another engine, i would take the cam and the rest of the lifters since you gotta take all that stuff off to get to just one lifter anyway. thats the safe way of doing it at least. if you just swap one lifter, you run the risk of a flat cam. flat cams suck, ive had them happen to me before.
I'm pretty sure you can put new lifters on an old cam, I think the issue is putting used lifters on different cam lobes than they started with, be it a new cam, old cam, or even different lobes of the same cam.
At this point I'm purely speculating, but I'd bet the lifter tops get dished to the shape of the cam lobes. New flat lifters will dish to match a used or new cam, but lifters that are already dished would try to wear the cam lobes to match, which you definitely wouldn't want.
Wear patterns on a lifter that randomly rotates?
Please don't tell my engines it can't be done.....they will be really disappointed.

Exactly what sort of negative results are supposed to happen?
NoS, on older lifters there is a wear pattern that concaves at the center, the cam will wear in the opposite fashion, this wear is usually very specific to the cam and lifter, so swapping one used cam to another used lifter will usually cause problems. Remember this is especially so of high mileage vehicles. I strongly recommend that you buy new. Now that having been said, you can use new lifters on an old cam without a problem.
The most negative thing that could happen is that with the different wear pattern there will be places on the cam and lifters were all of the spring pressure will be on the area of the cam that does not match, this will cause a hot spot on the cam and then, well you get the idea.
Oh and just to be OCD, PC and Technically correct they are Cam Followers, I had this forcefully pointed out to me by a Youg'in that was still wet behind ears, "of course they are cam followers i though, rolling my eyes as I reminisced about working for Fiat in 1975, with DOHC engines when this boy was still a gleam in his fathers eye". Anyway, "lifters" fits and we all know what you are talking about.
Andrew, you are correct as usual