I believe Pinball Rescue has them:

http://www.pinballrescue.net/Decals_Other.html

^^^Great guys to deal with!^^^

I know this is a super old post but too am looking for the bat stickers/decals for my 1972 Grand Slam restoration. Anyone have any leads on these since the above link is dead?

These (I think) are from Inkochnito and I'll provide the link so you can consider donating. Having said that, I can't find the exact file on his website again! http://www.pinballrebel.com/pinball/cards/

Print these onto clear waterslide decals using an inkjet. My waterslide requires a quick spray of clear coat, then soak in water for 30 seconds and slide onto the flipper. Works a treat.

profootball flipper decals.pdf