Using 0.8 and 0.7 in same Datadir?

[luv2drnkbr]

First, let me say, no coins are in the wallet in this directory, so I don't care if I've screwed things up.  (I'm on Windows.) I got lukejr's latest next test, and have been running that, but then when I opened up the standard 0.7.1 client, it is re-downloading blocks that I know the nexttest already downloaded. Is it messing things up to be running these with the same datadir option enabled? The colored coins Armory only reads the blockchain as updated from the 0.7 version, and I'd like to try that out.