As long as the mah rating on the charger is lower than the mah of the battery, it will work fine.
I can confirm this will work the other way around:
I have one of the first "auto eGO" batteries, uses a standard 510 eGo charger usually.
I have an old cig-case KR808 PCC which had fallen into disuse, so I added a 808/510 adapter and used it to charge my Auto eGo.
The PCC states on its label it outputs 4.3V @ 350mAh, designed for KR808 batteries (it's one of the cheapie PCCs). This is fairly close, both in voltage and current to the standard ego charger (4.2V @ 420mAh).
I have been using this PCC for charging in this manner for months with no problems. Can't close the lid while it is charging, but just sits on my bureau all the time anyway...
Provided you have adapters that will mate 510/808, and the current isn't too high (I also recommend never using a true eGo charger on an 808 stick, or 510 stick for that matter), it should work.