Short answer: yes.
Longer answer, with these mics + a battery box you'll get OK recordings, you will have to add gain in post. You can crank up the gain on the av500 and that will add about 10db or so, but you will probably want to add more.
I haven't used this bbox with these mics, but I've used this one
http://www.soundprofessionals.com/cgi-bin/gold/item/SP-SPSB-6 which I would guess is the same electronically. I recorded for a while with just mics + batter box (into a JB3) and got great sounding shows, but now that I use a preamp they're sounding even better. (You can search the forums here for more info on battery box vs preamp).
Note that you will have to use the adapter dongle to use line in (mobile adapter?) as the 1/8 plug is output only.
Personally for the money you're spending, I would check out Chris Church's mics/preamps on ebay (such as
http://cgi.ebay.com/STEREO-MICROPHONES-PREAMP-4-MINIDISC-DAT-MD-MP3_W0QQitemZ260054111491QQihZ016QQcategoryZ3281QQcmdZViewItem ) you could get both mics + a pre which would probably serve you better. (note that I haven't used Chris's mics, but I've read great things about them here. I've have his st9100 preamp and am very happy with it).
Just a note as far as the av500. I gave up using mine as a recorder, I had a few times where it said it was saving the file and never did, and even more times where the recorder would be powered off when I checked it after a show (with no recording saved). Perhaps it was something with my unit - your mileage may vary...