We are cleaning out our attic and are about to dump several old computers my wife salvaged (with written permission) when she worked for a major Mac software developer.  Among them are some PPCs and Quadras.  One Quadra is marked “Not for Resale”.  This marking appears to be from the factory.  This box is unusual in that it has extra cards providing multiple serial ports.  We have not had it booted up in several years.

Does anybody have any idea whether it’s worth more than salvage or not?

It depends if it has any unusual capabilities. If it’s a usual Quadra with a a ‘not for resale’ sticker, then it’s not worth that much… Try booting it up to see if it has any special powers on the software side.