Sigma 170-500mm APO for Pentax - Compatibility?

Hi - I have one of the above lenses for sale (elsewhere) and I'm trying to pin down what cameras it's compatible with.
I was using it with an adaptor on a Lumix - so have no idea what bodies it's actually meant to fully work with - eg Auto-focus functionality.
Can anyone please help me with this?
I've tried looking all over the place online, but so far to no avail.
Have contacted Sigma directly, but they've yet to get back to me on this.
So any help would be greatly appreciated...

Cheers!

This might help
http://www.pentaxforums.com/userreviews/sigma-170-500mm-f5-6-3-apo.html

I had already been on that page Dingo - but hadn't considered looking into the "Pentax KAF3 (in-lens AF only) " aspect of the list.
Ie I didn't realise there might be a KAF2, or any other type of mount/compatibility issue.
So, where do I get a list of KAF3 bodies ?

Ok - so my potential buyer has a Pentax K-m - which I've managed to work out uses a KAF2 mount.
Are KAF3 lenses (like my Sigma here), KAF2 backward compatible? Or will it only work on bodies which are KAF3?
As you can tell, I'm a green about the gills relating to this sort of stuff...

Just found what looks to be a fantastically useful list.
Many thanks to mosphotos.com !!!!

http://www.mosphotos.com/PentaxLensCompatibility.html

Looks like my potential buyer could be in luck as his K-m appears to be SDM/DC friendly.
"KAF3: This is a crippled KAF2 mount without the autofocus drive shaft. Lenses with the KAF3 mount will only autofocus on camera bodies with support for SDM and DC autofocus. "

K-m has SDM/DC autofocus (apparently - according to this list) - so this lens should work fine then?