Mostly, no. The MacBook might boot to the DVD from the iMac, but if it allows you to install, don't expect the MacBook to run well. The hardware drivers for your Mac won't be installed. Gray disks are machine specific, and only intended to be used with the model they came with.
More than likely, you'll get a "No" symbol when trying to boot the disk.
If you can't locate the gray disks for the MacBook, you can order replacements from Apple. It's about $40 for both disks and shipping. They'll need your Mac's serial number to ensure you get the correct disks.
Or, depending on what level of Snow Leopard the MacBook came with, you may be able to use the retail Snow Leopard, 10.6.3 disk. Those are $20. Don't just run out and buy one, though. It will only boot Intel based Macs that came with 10.6.3 or earlier. My Mac Pro came with 10.6.4, and the retail disk will not boot this Mac.